Enhancing 3D Visual Odometry with Single-Camera Stereo Omnidirectional Systems

We explore low-cost solutions for efficiently improving the 3D pose estimation problem of a single camera moving in an unfamiliar environment. The visual odometry (VO) task -- as it is called when using computer vision to estimate egomotion -- is of particular interest to mobile robots as well as humans with visual impairments. The payload capacity of small robots like micro-aerial vehicles (drones) requires the use of portable perception equipment, which is constrained by size, weight, energy consumption, and processing power. Using a single camera as the passive sensor for the VO task satisfies these requirements, and it motivates the proposed solutions presented in this thesis. To deliver the portability goal with a single off-the-shelf camera, we have taken two approaches: The first one, and the most extensively studied here, revolves around an unorthodox camera-mirrors configuration (catadioptrics) achieving a stereo omnidirectional system (SOS). The second approach relies on expanding the visual features from the scene into higher dimensionalities to track the pose of a conventional camera in a photogrammetric fashion. The first goal has many interdependent challenges, which we address as part of this thesis: SOS design, projection model, adequate calibration procedure, and application to VO. We show several practical advantages for the single-camera SOS due to its complete 360-degree stereo views, that other conventional 3D sensors lack due to their limited field of view. Since our omnidirectional stereo (omnistereo) views are captured by a single camera, a truly instantaneous pair of panoramic images is possible for 3D perception tasks. Finally, we address the VO problem as a direct multichannel tracking approach, which increases the pose estimation accuracy of the baseline method (i.e., using only grayscale or color information) under the photometric error minimization as the heart of the “direct” tracking algorithm. Currently, this solution has been tested on standard monocular cameras, but it could also be applied to an SOS. We believe the challenges that we attempted to solve have not been considered previously with the level of detail needed for successfully performing VO with a single camera as the ultimate goal in both real-life and simulated scenes

Desarrollo de la infraestructura y reducción de la pobreza: el caso peruano

In recent years, economic growth and the development of social programs have contributed significantly to poverty reduction in Peru. In this process, the development of infrastructure has been very important in reducing the long term vulnerability of households.This paper examines the role of infrastructure in reducing poverty in households in Peru within a dynamic perspective of poverty and under an asset-based approach. To do this, we estimate Logit models to reflect the impact of different types of infrastructure on the likelihood of being poor in Peru. We also estimate static panel data models (fixed and random effects) to reflect the impact of the different types of infrastructure on the spending ofPeruvian households. Both groups of models are based on information at the household level for the years 2007-2010 from the Peruvian official household survey provided by INEI. These impacts are estimated considering the sex of the household head and the area of residence(urban or rural). For static panel data models, we estimate the impact of the different types of infrastructure on household spending distinguishing whether they are transient poor or chronically poor. Given the data constraints at the household level in Peru, we only analyze the following infrastructures throughout the document: water, sewage, electricity and telecommunications. From the results, we verify a significant and different impact of the various types of infrastructure on poverty according to the area of residence and the gender of the household head. Similarly, we verify a significant and different impact of infrastructure on the types of poverty (transient and chronic poverty).Infraestructura, pobreza, ingresos, enfoque de activos, dinámica de la pobreza.

Session-based concurrency in Maude:Executable semantics and type checking

Session types are a well-established approach to communication correctness in message-passing processes. Widely studied from a process calculi perspective, here we pursue an unexplored strand and investigate the use of the Maude system for implementing session-typed process languages and reasoning about session-typed process specifications. We present four technical contributions. First, we develop and implement in Maude an executable specification of the operational semantics of a session-typed π-calculus by Vasconcelos. Second, we also develop an executable specification of its associated algorithmic type checking, and describe how both specifications can be integrated. Third, we show that our executable specification can be coupled with reachability and model checking tools in Maude to detect well-typed but deadlocked processes. Finally, we demonstrate the robustness of our approach by adapting it to a higher-order session π-calculus, in which exchanged values include names but also abstractions (functions from names to processes). All in all, our contributions define a promising new approach to the (semi)automated analysis of communication correctness in message-passing concurrency

Las ontologías en la ingeniería de software: un acercamiento de dos grandes áreas del conocimiento

Los conceptos ontológicos se suelen acercar más a la ingeniería del conocimiento, por lo que los ingenieros del software no los suelen aplicar para resolver problemas de su área. Es necesario que los ingenieros de software se apropien de las ontologías, pues éstas proporcionan un vocabulario común, que podría contribuir en la solución de problemas recurrentes en ingeniería del software, tales como la dificultad de la comunicación entre analista e interesado para definir los requisitos de un sistema, la baja reutilización de componentes y la escasa generación automática de código, entre otros. En este artículo se presenta un primer enlace entre las ontologías y la ingeniería de software mediante la recopilación y análisis de la literatura relativa a la utilización de las ontologías en las diferentes fases del ciclo de vida de un producto de software

Arquitectura Computacional para la Inferencia deuna CNN Cuantizada para Detectar FibrilaciónAuricular

Atrial Fibrillation is a common cardiac arrhythmia, which is characterized by an abnormal heartbeat rhythm that can be life-threatening. Recently, researchers have proposed several Convolutional Neural Networks (CNNs) to detect Atrial Fibrillation. CNNs have high requirements on computing and memory resources, which usually demand the use of High Performance Computing (eg, GPUs). This high energy demand is a challenge for portable devices. Therefore, efficient hardware implementations are required. We propose a computational architecture for the inference of a Quantized Convolutional Neural Network (Q-CNN) that allows the detection of the Atrial Fibrillation (AF). The architecture exploits data-level parallelism by incorporating SIMD-based vector units, which is optimized in terms of computation and storage and also optimized to perform both the convolutional and fully connected layers. The computational architecture was implemented and tested in a Xilinx Artix-7 FPGA. We present the experimental results regarding the quantization process in a different number of bits, hardware resources, and precision. The results show an accuracy of 94% accuracy for 22-bits. This work aims to be the basis for the future implementation of a portable, low-cost, and high-reliability device for the diagnosis of Atrial Fibrillation.La fibrilación auricular es una arritmia cardíaca común, que se caracte-riza por un ritmo cardíaco anormal que puede poner en peligro la vida.Recientemente, se han propuesto varias Redes Neuronales Convoluciona-les (CNNs, por sus siglas en inglés) para detectar la fibrilación auricular.Las CNN tienen altos requisitos de recursos informáticos y de memoria,lo que generalmente demanda el uso Computación de Altro Rendimientocomo por ejemplo GPUs. Esta alta demanda de energía es un desafío pa-ra los dispositivos portátiles. Por lo tanto, se requieren implementacionesde hardware eficientes. Proponemos una arquitectura computacional pa-ra la inferencia de una Red Neural Convolucional Cuantizada (Q-CNN)que permite la detección de la Fibrilación Auricular (FA). La arquitecturaaprovecha el paralelismo a nivel de datos, incorporando unidades vecto-riales basadas en SIMD, que están optimizadas en términos de cálculoy almacenamiento. El diseño también se optimizó para realizar tanto lascapas convolucionales como las capas completamente conectadas. La ar-quitectura computacional se implementó y probó en una FPGA XilinxArtix-7. Presentamos los resultados experimentales con respecto al proce-so de cuantización en un número diferente de bits, recursos de hardwarey precisión. Los resultados muestran una precisión del 94 % para 22 bits.Este trabajo pretende ser la base para la futura implementación de undispositivo portátil, de bajo costo y alta confiabilidad para el diagnósticode Fibrilación Auricular

Forest fragmentation and landscape connectivity changes in Ecuadorian mangroves: some hope for the future?

This study investigates the impact of fragmentation on Ecuador’s coastal mangrove forests. Fragmentation is identified as a primary cause of aquatic ecosystem degradation. We analyzed the relationship between habitat loss, fragmentation, and mangrove connectivity through a multitemporal approach using Global Mangrove Watch and fragmentation and connectivity metrics. The terrain was divided into 10 km2 hexagons, and six fragmentation metrics were calculated. A Getis–Ord Gi* statistical analysis was used to identified areas with the best and worst conservation status, while connectivity analyses were performed for a generic species with a 5 km dispersion. Findings revealed widespread mangrove fragmentation in Ecuador, with geographical differences between the insular region (Galapagos) and the mainland coast. Minimal loss or even expansion of mangrove forests in areas like the Galapagos Islands contrasted with severe fragmentation along the mainland coast. Transformation of forests into fisheries, mainly prawn factories, was the primary driver of change, while only a weak correlation was observed between mangrove fragmentation and conversion to agriculture, which accounts for less than 15% of all deforestation in Ecuador. Fragmentation may increase or decrease depending on the management of different deforestation drivers and should be considered in large-scale mangrove monitoring. Focusing only on mangrove deforestation rates in defining regional conservation priorities may overlook the loss of ecosystem functions and fragmentation

Study of multi black hole and ring singularity apparent horizons

We study critical black hole separations for the formation of a common apparent horizon in systems of $N$ - black holes in a time symmetric configuration. We study in detail the aligned equal mass cases for $N=2,3,4,5$, and relate them to the unequal mass binary black hole case. We then study the apparent horizon of the time symmetric initial geometry of a ring singularity of different radii. The apparent horizon is used as indicative of the location of the event horizon in an effort to predict a critical ring radius that would generate an event horizon of toroidal topology. We found that a good estimate for this ring critical radius is $20/(3\pi) M$. We briefly discuss the connection of this two cases through a discrete black hole 'necklace' configuration.Comment: 31 pages, 21 figure

Explosive Radiation of Malpighiales Supports a Mid-Cretaceous Origin of Modern Tropical Rain Forests

Fossil data have been interpreted as indicating that Late Cretaceous tropical forests were open and dry adapted and that modern closed-canopy rain forest did not originate until after the Cretaceous-Tertiary (K/T) boundary. However, some mid-Cretaceous leaf floras have been interpreted as rain forest. Molecular divergence-time estimates within the clade Malpighiales, which constitute a large percentage of species in the shaded, shrub, and small tree layer in tropical rain forests worldwide, provide new tests of these hypotheses. We estimate that all 28 major lineages (i.e., traditionally recognized families) within this clade originated in tropical rain forest well before the Tertiary, mostly during the Albian and Cenomanian (112 - 94 Ma). Their rapid rise in the mid-Cretaceous may have resulted from the origin of adaptations to survive and reproduce under a closed forest canopy. This pattern may also be paralleled by other similarly diverse lineages and supports fossil indications that closed-canopy tropical rain forests existed well before the K/T boundary. This case illustrates that dated phylogenies can provide an important new source of evidence bearing on the timing of major environmental changes, which may be especially useful when fossil evidence is limited or controversial.Organismic and Evolutionary Biolog

La nueva interpretación delito de prevaricato por acción de funcionarios judiciales en la jurisprudencia de la Corte Suprema de Justicia

Jurisprudential commentComentario jurisprudencia