Price Formation and Real Estate Characteristics Residential Real Estate, Lisbon - Portugal

Análisis del proceso de formación de precios en el mercado residencial de Lisboa desde el punto de vista de la eliminación de los aspectos subjetivos de la apreciación por el tasador de las características de los inmuebles

Shadow Analysis of Soil Surface Roughness Compared to the Chain Set Method and Direct Measurement of Micro-relief.

Erosion potential and the effects of tillage can be evaluated from quantitative descriptions of soil surface roughness. The present study therefore aimed to fill the need for a reliable, low-cost and convenient method to measure that parameter. Based on the interpretation of micro-topographic shadows, this new procedure is primarily designed for use in the field after tillage. The principle underlying shadow analysis is the direct relationship between soil surface roughness and the shadows cast by soil structures under fixed sunlight conditions. The results obtained with this method were compared to the statistical indexes used to interpret field readings recorded by a pin meter. The tests were conducted on 4-m2 sandy loam and sandy clay loam plots divided into 1-m2 subplots tilled with three different tools: chisel, tiller and roller. The highly significant correlation between the statistical indexes and shadow analysis results obtained in the laboratory as well as in the field for all the soil?tool combinations proved that both variability (CV) and dispersion (SD) are accommodated by the new method. This procedure simplifies the interpretation of soil surface roughness and shortens the time involved in field operations by a factor ranging from 12 to 20.

1000x shadow-free mirror-based Köhler concentrator

A new design for a photovoltaic concentrator, the most recent advance based on the Kohler concept, is presented. The system is mirror-based, and with geometry that guaranties a maximum sunlight collection area (without shadows, like those caused by secondary stages or receivers and heat-sinks in other mirror-based systems). Designed for a concentration of 1000x, this off axis system combines both good acceptance angle and good irradiance uniformity on the solar cell. The advanced performance features (concentration-acceptance products ?CAP- about 0.73 and affordable peak and average irradiances) are achieved through the combination of four reflective folds combined with four refractive surfaces, all of them free-form, performing Köhler integration 2 . In Köhler devices, the irradiance uniformity is not achieved through additional optical stages (TIR prisms), thus no complex/expensive elements to manufacture are required. The rim angle and geometry are such that the secondary stage and receivers are hidden below the primary mirrors, so maximum collection is assured. The entire system was designed to allow loose assembly/alignment tolerances (through high acceptance angle) and to be manufactured using already well-developed methods for mass production, with high potential for low cost. The optical surfaces for Köhler integration, although with a quite different optical behavior, have approximately the same dimensions and can be manufactured with the same techniques as the more traditional secondary optical elements used for concentration (typically plastic injection molding or glass molding).

Factors influencing metal price selection in mining feasibility studies

The mineral price assigned in mining project design is critical to determining the economic feasibility of a project. Nevertheless, although it is not difficult to find literature about market metal prices, it is much more complicated to achieve a specific methodology for calculating the value or which justifications are appropriate to include. This study presents an analysis of various methods for selecting metal prices and investigates the mechanisms and motives underlying price selections. The results describe various attitudes adopted by the designers of mining investment projects, and how the price can be determined not just by means of forecasting but also by consideration of other relevant parameters.

Analysis of the Iberian Power Forward Price Formation

The price formation of the Iberian Energy Derivatives Market-the power futures market-starting in July 2006, is assessed until November 2011, through the evolution of the difference between forward and spot prices in the delivery period (“ex-post forward risk premium”) and the comparison with the forward generation costs from natural gas (“clean spark spread”). The premium tends to be positive in all existing mechanisms (futures, Over-the-Counter and auctions for catering part of the last resort supplies). Since year 2011, the values are smaller due to regulatorily recognized prices for coal power plants. The power futures are strongly correlated with European gas prices. The spreads built with prompt contracts tend also to be positive. The biggest ones are for the month contract, followed by the quarter contract and then by the year contract. Therefore, gas fired generation companies can maximize profits trading with contracts of shorter maturity.

An Empirical Analysis of the Spanish Gas Price Structure

We can say without hesitation that in energy markets a throughout data analysis is crucial when designing sophisticated models that are able to capture most of the critical market drivers. In this study we will attempt to investigate into Spanish natural gas prices structure to improve understanding of the role they play in the determination of electricity prices and decide in the future about price modelling aspects. To further understand the potential for modelling, this study will focus on the nature and characteristics of the different gas price data available. The fact that the existing gas market in Spain does not incorporate enough liquidity of trade makes it even more critical to analyze in detail available gas price data information that in the end will provide relevant information to understand how electricity prices are affected by natural gas markets. In this sense representative Spanish gas prices are typically difficult to explore given the fact that there is not a transparent gas market yet and all the gas imported in the country is negotiated and purchased by private companies at confidential terms.

Electricity price forecasting accounting for renewable energies: optimal combined forecasts

Electricity price forecasting is an interesting problem for all the agents involved in electricity market operation. For instance, every profit maximisation strategy is based on the computation of accurate one-day-ahead forecasts, which is why electricity price forecasting has been a growing field of research in recent years. In addition, the increasing concern about environmental issues has led to a high penetration of renewable energies, particularly wind. In some European countries such as Spain, Germany and Denmark, renewable energy is having a deep impact on the local power markets. In this paper, we propose an optimal model from the perspective of forecasting accuracy, and it consists of a combination of several univariate and multivariate time series methods that account for the amount of energy produced with clean energies, particularly wind and hydro, which are the most relevant renewable energy sources in the Iberian Market. This market is used to illustrate the proposed methodology, as it is one of those markets in which wind power production is more relevant in terms of its percentage of the total demand, but of course our method can be applied to any other liberalised power market. As far as our contribution is concerned, first, the methodology proposed by García-Martos et al(2007 and 2012) is generalised twofold: we allow the incorporation of wind power production and hydro reservoirs, and we do not impose the restriction of using the same model for 24h. A computational experiment and a Design of Experiments (DOE) are performed for this purpose. Then, for those hours in which there are two or more models without statistically significant differences in terms of their forecasting accuracy, a combination of forecasts is proposed by weighting the best models(according to the DOE) and minimising the Mean Absolute Percentage Error (MAPE). The MAPE is the most popular accuracy metric for comparing electricity price forecasting models. We construct the combi nation of forecasts by solving several nonlinear optimisation problems that allow computation of the optimal weights for building the combination of forecasts. The results are obtained by a large computational experiment that entails calculating out-of-sample forecasts for every hour in every day in the period from January 2007 to Decem ber 2009. In addition, to reinforce the value of our methodology, we compare our results with those that appear in recent published works in the field. This comparison shows the superiority of our methodology in terms of forecasting accuracy.

Impact of introducing longer and heavier vehicles on regional consumer price index and Spanish road freight transport system

This paper applies an integrated modeling approach to the case of Spain; the approach is based on a random utility-based multiregional input-output model and a road transport network model for assessing the effect of introducing longer and heavier vehicles (LHVs) on the regional consumer price index (CPI) and on the transportation system. The approach strongly supports the concept that changes in transport costs derived from the LHV allowance as well as the economic structure of regions have direct and indirect effects on the economy and on the transportation system. Results show that the introduction of LHVs might reduce prices paid by consumers for a representative basket of goods and services in the regions of Spain and would also lead to a reduction in the regional CPI. In addition, the magnitude and extent of changes in the transportation system are estimated by using the commodity-based structure of the approach to identify the effect of traffic changes on traffic flows and on pollutant emissions over the whole network.

Hacia una arquitectura de procesos : transformaciones disciplinares a través de la Computación en los modelos de Alexander, Negroponte y Price

La premisa inicial de la tesis examina cómo las secuelas de Segunda Guerra mundial motivaron una revisión general de la Ciencia y procuraron una nueva relación entre el hombre y su entorno. Matemáticas, Física y Biología gestaron las Ciencias de la Computación como disciplina de convergencia. En un momento de re-definición del objeto científico, una serie de arquitectos vislumbraron la oportunidad para transformar ciertas convenciones disciplinares. Mediante la incorporación de ontologías y procedimientos de cibernética y computación, trazaron un nuevo espacio arquitectónico. Legitimados por un despegue tecnológico incuestionable, desafían los límites de la profesión explorando campos abiertos a nuevos programas y acciones; amplían el dominio natural de la Arquitectura más allá del objeto(terminado) hacia el proceso(abierto). Se da inicio a la tesis describiendo los antecedentes que conducen a ese escenario de cambio. Se anotan aspectos de Teoría de Sistemas, Computación, Biología y de ciertos referentes de Arquitectura con relevancia para esa nuevo planteamiento. En esos antecedentes residen los argumentos para orientar la disciplina hacia el trabajo con procesos. La linea argumental central del texto aborda la obra de Christopher Alexander, Nicholas Negroponte y Cedric Price a través de una producción teórica y práctica transformada por la computación, y examina la contribución conceptual de cada autor. El análisis comparado de sus modelos se dispone mediante la disección de tres conceptos convergentes: Sistema, Código y Proceso. La discusión crítica se articula por una triangulación entre los autores, donde se identifican comparando por pares las coincidencias y controversias entre ellos. Sirve este procedimiento al propósito de tender un puente conceptual con el escenario arquitectónico actual estimando el impacto de sus propuestas. Se valora su contribución en la deriva del programa cerrado a la especulación , de lo formal a lo informal, de lo único a lo múltiple; del estudio de arquitectura al laboratorio de investigación. Para guiar ese recorrido por la significación de cada autor en el desarrollo digital de la disciplina, se incorporan a la escena dos predicados esenciales; expertos en computación que trabajaron de enlace entre los autores, matizando el significado de sus modelos. El trabajo de Gordon Pask y John Frazer constituye el vehículo de transmisión de los hallazgos de aquellos años, prolonga los caminos iniciados entonces, en la arquitectura de hoy y la que ya se está diseñando para mañana. ABSTRACT The initial premise of the thesis examines how the aftermath of second world war motivated a general revision of science and procure the basis of a new relation between mankind and its environment. Mathematics, Physics, and Biology gave birth to the Computer Sciences as a blend of different knowledge and procedures. In a time when the object of major sciences was being redefined, a few architects saw a promising opportunity for transforming the Architectural convention. By implementing the concepts, ontology and procedures of Cybernetics, Artificial Intelligence and Information Technology, they envisioned a new space for their discipline. In the verge of transgression three prescient architects proposed complete architectural systems through their writings and projects; New systems that challenged the profession exploring open fields through program and action, questioning the culture of conservatism; They shifted architectural endeavor from object to process. The thesis starts describing the scientific and architectural background that lead to that opportunity, annotating aspects of Systems Theory, Computing, Biology and previous Architecture form the process perspective. It then focuses on the Works of Christopher Alexander, Nicholas Negroponte and Cedric Price through their work, and examines each authors conceptual contribution. It proceeds to a critical analysis of their proposals on three key converging aspects: system, architectural encoding and process. Finally, the thesis provides a comparative discussion between the three authors, and unfolds the impact of their work in todays architectural scenario. Their contribution to shift from service to speculation, from formal to informal , from unitary to multiple; from orthodox architecture studio to open laboratories of praxis through research. In order to conclude that triangle of concepts, other contributions come into scene to provide relevant predicates and complete those models. A reference to Gordon Pask and John Frazer is then provided with particular interest in their role as link between those pioneers and todays perspective, pushing the boundaries of both what architecture was and what it could become.

Experimentación radical italiana en torno al night-club. Warhol-MacLuhan-Price y la arquitectura eléctrica de los años 60.

La segunda mitad de los años 60, ese convulso periodo generador de experiencias largamente revisitadas, es testigo también de un curioso fenómeno en Italia que, vinculado al auge de los locales nocturnos en Estados Unidos y a un intenso clima de emancipación social, utiliza estos nuevos “palacios de la diversión” como fuente de inspiración ideológica al ser percibidos entre los jóvenes arquitectos y diseñadores radicales italianos como un laboratorio experimental estilístico y funcional capaz de generar modelos para un nuevo orden social ligado al entretenimiento. La intensidad productiva de estos años da como resultado multitud de propuestas donde la arqui­tectura actúa como catalizadora de una pulsión social que mezcla en el mismo espa­cio la vanguardia cultural y experimental más radical con el fenómeno de masas de la sociedad del espectáculo, permitiendo a la industria del placer ocupar sin complejos una posición clave en el discurso de una nueva generación que traslada intenciona­damente su interés desde la forma construida a la producción de ambientes artificia­les, electrónicamente amplificados, demostrando al mismo tiempo su compromiso con las formas y la lógica de las nuevas tecnologías.