3,117 research outputs found
Strengthening financial innovations in energy supply projects for rural exploitations in developing countries
Sustainable energy supply models are needed to achieve the Millennium Development Goals established by the United Nations for 2015. On the other hand, sustainability of agricultural exploitations in rural areas is a pre-requisite to achieve the objective of halving the proportion of people that lives in poverty, and productivity of such exploitations is closely related to energy supply. This article analyses the results of a survey of experts, suggesting that there may be good chances to innovate in the financing of agricultural electrification projects in developing countries. The experts’ opinion suggests that new sources of financing could be mobilised and oriented towards the promotion of sustainable initiatives in developing countries. Financial mechanisms should be adapted to the characteristics of decentralised systems of energy production with renewable sources or with mixed technologies, in order to overcome the barriers derived from the high initial price of the applications, and to the specific conditions of the agricultural sector. The participation of funds from the beneficiaries and the incorporation of the beneficiaries in the initial phases of project organisation would allow for the development of productive solutions with a higher potential to generate resources and to articulate sustainable proposals. r 2007 Elsevier Ltd. All rights reserved
Evolución histórica reciente y situación actual del sector eléctrico español
En este artículo se analizan los efectos que tuvo sobre el Sector Eléctrico español el sistema regulador vigente en España, el denominado Marco Legal Estable, desde su implantación a comienzos de 1988 hasta que se inició el proceso de liberalización a mediados de la década de los 90, y como este sector, que pudo sanearse financieramente durante este período, todavía se enfrenta a retos importantes en un contexto económico de internacionalización y desregulación progresivas
Distributed power generation in the United States
With electricity consumption increasing within the UnitedStates, new paradigms of delivering electricity are required in order to meet demand. One promising option is the increased use of distributedpowergeneration. Already a growing percentage of electricity generation, distributedgeneration locates the power plant physically close to the consumer, avoiding transmission and distribution losses as well as providing the possibility of combined heat and power. Despite the efficiency gains possible, regulators and utilities have been reluctant to implement distributedgeneration, creating numerous technical, regulatory, and business barriers. Certain governments, most notable California, are making concerted efforts to overcome these barriers in order to ensure distributedgeneration plays a part as the country meets demand while shifting to cleaner sources of energy
System Dynamics Simulation to Test Operational Policies in the Milk-Cheese Supply Chain Case study: Piar Municipality, Bolivar State, Venezuela.
With the purpose of detecting the impact that variations of demand cause in the milk-cheese supply chain, and determining how the operational policies of capacity, inventories or labor force can mitigate this impact, a system dynamics simulation model has been designed based on a survey conducted on a sample of cheese manufacturers and their links with milk farms, transportation companies and cheese distributors. This supply chain will be consolidated when a milk center that will collect the raw milk is completed. From this center, and after adequate treatment, milk will be distributed to the different cheese manufacturers in the supply chain. Managing adequately the milk-cheese supply chain represents an important challenge due to the short life of these products. Although this study was done in a region in Latin America, its results can be applicable to food supply chains by introducing some modifications. The milk-cheese supply chain in this case study contemplates three milk producers, one milk center, five cheese producers and several distributing agents. These companies operate individually under normal conditions, but they have understood that their integration in a supply chain improves the competitiveness of all its members. That is to say, the sum is greater than the parts. For its initial design a simulation software model is used in which the resources of the supply chain are optimized. Later the product of this optimization facilitates some initial values to be used in the system dynamics model in which causeeffect or influence relationships have been previously established considering the most representative variables. Finally, changes in operational policies that can reduce the level of pending orders in the supply chain are tested using other simulation software. The main contribution of this research is that it can serve as support or contribute to reduce the uncertainty in the decision making process of the supply chain management due to the speed with which individual or combined policies can be analyzed. In response to a variation of demand the most adequate policy may be selected and that can be done before the policy is implemented
Probabilistic localization of gas emission areas with a mobile robot in indoor environments
This work deals with the problem of gas source localization by a mobile robot with gas-sensing capabilities. Particularly, we address the problem for the case of indoor environments, where the presence of obstacles and the possibly complex
structure with multiple rooms, inlets and outlets provoke the chaotic dispersion of the gases. Under these challenging conditions, where traditional approaches based on tracking or mathematical modeling of the plume cannot be applied, we propose a two-stage methodology to split the search into coarse and fine localization. Focusing on the broad localization, we contribute with a novel approach to estimate, from a set of sparse observations, the likelihood of different regions in the environment to hold a gas source. Experiments demonstrate that our approach is suitable to locate gas emission sources.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Drawing the Horton Set in an Integer Grid of Minimum Size
In 1978 Erd\H os asked if every sufficiently large set of points in general
position in the plane contains the vertices of a convex -gon, with the
additional property that no other point of the set lies in its interior.
Shortly after, Horton provided a construction---which is now called the Horton
set---with no such -gon. In this paper we show that the Horton set of
points can be realized with integer coordinates of absolute value at most
. We also show that any set of points
with integer coordinates combinatorially equivalent (with the same order type)
to the Horton set, contains a point with a coordinate of absolute value at
least , where is a positive constant
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