Artificial Neural Nets with Interaction of Afferents

The aim is to obtain computationally more powerful, neuro physiologically founded, artificial neurons and neural nets. Artificial Neural Nets (ANN) of the Perceptron type evolved from the original proposal by McCulloch an Pitts classical paper [1]. Essentially, they keep the computing structure of a linear machine followed by a non linear operation. The McCulloch-Pitts formal neuron (which was never considered by the author’s to be models of real neurons) consists of the simplest case of a linear computation of the inputs followed by a threshold. Networks of one layer cannot compute anylogical function of the inputs, but only those which are linearly separable. Thus, the simple exclusive OR (contrast detector) function of two inputs requires two layers of formal neuron

Real-time fluid simulations under smoothed particle hydrodynamics for coupled kinematic modelling in robotic applications

Although solids and fluids can be conceived as continuum media, applications of solid and fluid dynamics differ greatly from each other in their theoretical models and their physical behavior. That is why the computer simulators of each turn to be very disparate and case-oriented. The aim of this research work, captured in this thesis book, is to find a fluid dynamics model that can be implemented in near real-time with GPU processing and that can be adapted to typically large scales found in robotic devices in action with fluid media. More specifically, the objective is to develop these fast fluid simulations, comprising different solid body dynamics, to find a viable time kinematic solution for robotics. The tested cases are: i) the case of a fluid in a closed channel flowing across a cylinder, ii) the case of a fluid flowing across a controlled profile, and iii), the case of a free surface fluid control during pouring. The implementation of the former cases settles the formulations and constraints to the latter applications. The results will allow the reader not only to sustain the implemented models but also to break down the software implementation concepts for better comprehension. A fast GPU-based fluid dynamics simulation is detailed in the main implementation. The results show that it can be used in real-time to allow robotics to perform a blind pouring task with a conventional controller and no special sensing systems nor knowledge-driven prediction models would be necessary.Aunque los sólidos y los fluidos pueden concebirse como medios continuos, las aplicaciones de la dinámica de sólidos y fluidos difieren mucho entre sí en sus modelos teóricos y su comportamiento físico. Es por eso que los simuladores por computadora de cada uno son muy dispares y están orientados al caso de su aplicación. El objetivo de este trabajo de investigación, capturado en este libro de tesis, es encontrar un modelo de dinámica de fluidos que se pueda implementar cercano al tiempo real con procesamiento GPU y que se pueda adaptar a escalas típicamente grandes que se encuentran en dispositivos robóticos en acción con medios fluidos. Específicamente, el propósito es desarrollar estas simulaciones de fluidos rápidos, que comprenden diferentes dinámicas de cuerpos sólidos, para encontrar una solución cinemática viable para robótica. Los casos probados son: i) el caso de un fluido en canal cerrado que fluye a través de un cilindro, ii) el caso de un fluido que fluye a través de un alabe controlado, y iii), el caso del control de un fluido de superficie libre durante el vertido. La implementación de estos primeros casos establece las formulaciones y limitaciones de aplicaciones futuras. Los resultados permitirán al lector no solo sostener los modelos implementados sino también desglosar los conceptos de la implementación en software para una mejor comprensión. En la implementación principal se consigue una simulación rápida de dinámica de fluidos basada en GPU. Los resultados muestran que esta implementación se puede utilizar en tiempo real para permitir que la robótica realice una tarea de vertido ciego con un controlador convencional sin que sea necesario algún sistema de sensado especial ni algún modelo predictivo basados en el conocimiento.Programa de Doctorado en Ingeniería Eléctrica, Electrónica y Automática por la Universidad Carlos III de MadridPresidente: Carmen Martínez Arévalo.- Secretario: Luis Santiago Garrido Bullón.- Vocal: Benjamín Hernández Arreguí

Hybrid Green Corridors in Arid Northern Mexico: Design for a Balance between Ecological and Non-Motorized Mobility Networks

Urban planning in Mexico has been going through intensive updating by the hand of the recently created Municipal Planning Institutes (IMPLANES). These institutes have emerged in the XXI century as a response to the inability to implement medium to long term planning efforts derived from an urban administration model determined by three year municipal government terms with no reelection as an option. Before the emergence of IMPLANES, decisions pertaining urban infrastructure were determined by mayors trying to leverage brief periods of time in the scale of urban administration and planning. IMPLANES have spent a significant part of their efforts updating the aged and conceptually obsolete –largely based on XX century zoning practices- urban plans of medium to large cities in the country. One of the frequent components added, as innovations, to the urban plans are green corridors and non-motorized mobility networks conceived as devices to structure what often are highly fragmented urban fabrics. Green corridors are planned on creeks, dry rivers, and rivers. Non-motorized mobility networks are planned on existing streets of various hierarchies. These 2 types of networks, are often planned as separate systems. The green corridors are associated to the production of public space/green areas and the non-motorized systems are related to mobility plans which typically include pedestrian, bicycle, and public transportation alternatives. The separation of green corridor and non-motorized mobility systems results in plans with complete spatial coverage for non-motorized mobility. But, it also results in plans which have proven to be unrealistic towards implementation. After some years of planning there are very few bicycle lanes built today. As bicycle transportation is slowly being accepted by the population, particularly young people, public budgets continue to be sucked away by expensive traditional car-oriented infrastructure. The intention of this paper is to propose that a hybrid network composed of integrated green corridors and non-motorized mobility can be more effective as a strategy towards implementation. While the spatial coverage might not be as extensive as the planned non-motorized networks on retrofitted streets, it is a coverage which can be targeted and centered on green corridors which, complemented by complete streets, can both deliver mobility, public space, and ecosystem services. This paper is the result of the design exploration of hybrid networks in applied academic studios. The inquiry is led by urban studies on 4 northern Mexico cities, 3 of which were supported by design studios in collaboration with the local IMPLANES. These studios fill the gap created by the lack of educational programs in landscape architecture and urban design in Mexico; while serving as an opportunity to learn by serving communities. The four cities were selected because of two different characteristics in their green corridor capacities: Chihuahua and Los Cabos possess networks already planned on natural drainage ways; Hermosillo and Mexicali have mostly artificial drainage ways found on irrigation and storm water management canals. All these four cities also share 2 other critical conditions relevant to the production of hybrid corridors: these are all semi-arid and arid cities. According to their urban plans, their average rainfall rates are 262.7 millimeters for Los Cabos; 427.2 mm for Chihuahua; 348 mm for Hermosillo; and 36 mm for Mexicali. Their natural landscapes are mostly composed of grasslands and desert scrub with the presence of trees only on intermittent riparian corridors and on mountain slopes. These corridors and massifs contain spatial and environmental quality but are threatened, destroyed, or polluted by urbanization. The four cities have insufficient green areas. According to recommendations by the World Health Organization, used as indicator by their urban plans, city dwellers need 9 square meters of green areas: Los Cabos has only 4 m2 per person; Chihuahua 3.7 m2; Hermosillo 6.19 m2; and Mexicali 2.1 m2

Econometric Modeling for the Analysis of the Influence of Safety Perceptions on Travelers’ Behavior

The objective of this research is to study the influence that safety perceptions have on travelers’ behavior in a broad array of choice contexts and investigate issues that have not been sufficiently addressed by the transportation literature, such as the influence of tangible attributes on perceptions and the influence of indicators’ complexity on the model estimates. Using three existing databases, we study the influence of risk perception on drivers' behavior, the influence of safety and comfort perceptions on individuals’ preferences for inland waterway passenger transportation, and the influence of these latent variables in the competition between BRT and motorcycle taxis. We design two ad-hoc surveys, the first one to study the influence of safety perceptions and some individual attitudes toward cycling, on the intention to use the public transportation integration on a bike and ride strategy. The second survey study safety and comfort perceptions of riding conventional feeder buses and auto-rickshaws as part of a BRT system. We demonstrate that tangible attributes have a significant effect on both the utility and the safety perception of individuals, which allows for the evaluation of policies related to latent variables and studying how a certain policy modifies safety perception. We also prove that the number of indicators per latent variable, the type of the scale and the granularity in which indicators are measured do affect the error variance of the measurement component. We show that the use of odd-numbered Likert scales contributes to a lower error variance of the measurement component

Control and command systems concepts from early work on a Mars Rover

We recover and develop some robotic systems concepts (on the light of present systems tools) that were originated for an intended Mars Rover in the sixties of the last century at the Instrumentation Laboratory of MIT, where one of the authors was involved. The basic concepts came from the specifications for a type of generalized robot inspired in the structure of the vertebrate nervous systems, where the decision system was based in the structure and function of the Reticular Formation (RF). The vertebrate RF is supposed to commit the whole organism to one among various modes of behavior, so taking the decisions about the present overall task. That is, it is a kind of control and command system. In this concepts updating, the basic idea is that the RF comprises a set of computing units such that each computing module receives information only from a reduced part of the overall, little processed sensory inputs. Each computing unit is capable of both general diagnostics about overall input situations and of specialized diagnostics according to the values of a concrete subset of the input lines. Slave systems to this command and control computer, there are the sensors, the representations of external environment, structures for modeling and planning and finally, the effectors acting in the external world