Learning, Prediction and Planning with Approximate Forward Models

The capacity to build internal representations of the world provides an agent with the opportunity to use them to act in its surroundings more appropriately. These internal representations may capture complex associations and keep track of the state of the agent and the environment. One of the most striking aspects of this phenomenon is that the agent may manipulate these internal representations to consider the distant future, and to formulate plans likely to lead to beneficial outcomes. Our treatment in this thesis considers this particular class of agents referred to as model-based. The behaviour of these agents is not only contingent upon the current sensory stream and their memory, but also based on hypothetical future sensory streams that are produced from potential sequences of actions. Throughout this thesis, there are two main themes that we explore and that are fundamental for advancing our understanding of model-based agents. The first is the agent's uncertainty about its environment and how it influences its decision-making. There are multiple aspects one could investigate about this relation. We analyse two specific scenarios. The first illustrates how it is possible to harness the agent's uncertainty to devise error-correction schemes. In the second, a probability distribution that defines the agent's current model is used to derive intrinsic utility signals to guide behaviour. The other main theme that permeates this thesis is the question of what are the aspects of the external world that should be stored and represented by an internal model? This question has important consequences for the design of learning objectives. As we will see in this thesis, we start with perhaps the most conceptually intuitive way to frame a learning objective for acquiring a world model. Namely, the assumption that the agent must be able to predict as accurately as possible its future observations. From this starting point, we progress towards learning objectives that introduce additional prediction targets or constraints to aim for a compressed and more essential representation of an observation. This theme concludes by trying to gain some perspective on whether it is possible, and even desirable, to attempt to have an internal model that tries to map the external observations, as we start to consider information-theoretic notions of relevance. Our results show that these design choices can have a profound effect on performance, even when the planning machinery is identical, and demonstrate the importance of building world models aligned with the agent's behavioural objectives

Factores determinantes en la selecci?n de vivienda social en el Per? : evidencia de un estudio en Chincha

Este estudio tuvo por objetivo determinar atributos m?s importantes que el comprador de vivienda social tiene en cuenta al momento de optar por una vivienda a fin de que las diferentes entidades privadas y no privadas las puedan tomar en cuenta al momento de realizar los dise?os de sus proyectos inmobiliarios de vivienda social. La hip?tesis planteada es que existe un grupo de factores que son determinantes en el momento de la decisi?n de compra de la vivienda social en nuestro pa?s. Adicionalmente se busca determinar el orden de importancia o preferencia entre estos factores

Plan de negocio para determinar la viabilidad econ?mica de la comercializaci?n de muebles auxiliares hechos de pl?stico reciclado, distribuidos a trav?s de las plataformas digitales (E-commerce) en Lima Moderna

El presente plan de negocio tiene como finalidad brindar una soluci?n ecofriendly al problema de la contaminaci?n ambiental en Lima, al tratamiento incorrecto que se le brinda a los residuos s?lidos como el pl?stico y al deteriorado consumo sostenible que tiene la poblaci?n lime?a. Lo antes mencionado se pretende mejorar a trav?s de la fabricaci?n y comercializaci?n de muebles para el hogar elaborados con pl?stico tratado. El objetivo principal del presente estudio fue determinar la viabilidad econ?mica del plan de negocio propuesto, el cual se basa en la comercializaci?n de muebles auxiliares elaborados de pl?stico reciclado distribuidos a trav?s de las plataformas digitales (E-commerce) en Lima Moderna. Se plante? una metodolog?a con enfoque mixto de investigaci?n, es decir, un estudio tanto cualitativo como cuantitativo y de alcance descriptivo; siendo el target market hombres y mujeres de los NSE A y B, con edades que oscilan entre los 25 a 39 a?os, cabezas de familia con gusto de dise?os de muebles ?nicos y exclusivos

Points to consider in cardiovascular disease risk management among patients with rheumatoid arthritis living in South Africa, an unequal middle income country

Background: It is plausible that optimal cardiovascular disease (CVD) risk management differs in patients with rheumatoid arthritis (RA) from low or middle income compared to high income populations. This study aimed at producing evidence-based points to consider for CVD prevention in South African RA patients. Methods: Five rheumatologists, one cardiologist and one epidemiologist with experience in CVD risk management in RA patients, as well as two patient representatives, two health professionals and one radiologist, one rheumatology fellow and 11 rheumatologists that treat RA patients regularly contributed. Systematic literature searches were performed and the level of evidence was determined according to standard guidelines. Results: Eighteen points to consider were formulated. These were grouped into 6 categories that comprised overall CVD risk assessment and management (n = 4), and specific interventions aimed at reducing CVD risk including RA control with disease modifying anti-rheumatic drugs, glucocorticoids and non-steroidal anti-inflammatory drugs (n = 3), lipid lowering agents (n = 8), antihypertensive drugs (n = 1), low dose aspirin (n = 1) and lifestyle modification (n = 1). Each point to consider differs partially or completely from recommendations previously reported for CVD risk management in RA patients from high income populations. Currently recommended CVD risk calculators do not reliably identify South African black RA patients with very high-risk atherosclerosis as represented by carotid artery plaque presence on ultrasound. Conclusions: Our findings indicate that optimal cardiovascular risk management likely differs substantially in RA patients from low or middle income compared to high income populations. There is an urgent need for future multicentre longitudinal studies on CVD risk in black African patients with RA