Water Reallocation in the Input-Output Model

Water reallocation between economic agents has been –and continues to be- the subject of a considerable amount of research. This paper proposes a method for evaluating how water is reallocated within the economy in response to changes in final demand and changes in the technical water needs of activities and consumers. The empirical application, which is for the Catalan economy, shows important asymmetries in the effects that exogenous inflows and changes in water technical requirements cause on water reallocation. In the process of water distribution, exogenous inflows mostly benefit agriculture and damage private consumers. On the other hand, increases in technical water requirements have negative effects on agriculture and positive effects on the other production activities. The results of the study suggest that agriculture is an important activity not only in terms of water distribution but also in terms of water reallocation due to changes in final demand and technical water needs. Keywords: Water reallocation, water distribution, exogenous shock, technical water needs.

On an asymptotic formula for the maximum voltage drop in a on-chip power distribution network

We present a new asymptotic formula for the maximum static voltage in a simplified model for on-chip power distribution networks of array bonded integrated circuits. In this model the voltage is the solution of a Poisson equation in an infinite planar domain whose boundary is an array of circular pads of radius ", and we deal with the singular limit Ɛ → 0 case. In comparison with approximations that appear in the electronic engineering literature, our formula is more complete since we have obtained terms up to order Ɛ15. A procedure will be presented to compute all the successive terms, which can be interpreted as using multipole solutions of equations involving spatial derivatives of functions. To deduce the formula we use the method of matched asymptotic expansions. Our results are completely analytical and we make an extensive use of special functions and of the Gauss constant G

The maximum voltage drop in an on-chip power distribution network: analysis of square, triangular and hexagonal power pad arrangements

A mathematical model of the voltage drop which arises in on-chip power distribution networks is used to compare the maximum voltage drop in the case of different geometric arrangements of the pads supplying power to the chip. These include the square or Manhattan power pad arrangement, which currently predominates, as well as equilateral triangular and hexagonal arrangements. In agreement with the findings in the literature and with physical and SPICE models, the equilateral triangular power pad arrangement is found to minimize the maximum voltage drop. This headline finding is a consequence of relatively simple formulas for the voltage drop, with explicit error bounds, which are established using complex analysis techniques, and elliptic functions in particular.

The maximum voltage drop in an on-chip power distribution network: analysis of square, triangular and hexagonal power pad arrangements

A mathematical model of the voltage drop which arises in on-chip power distribution networks is used to compare the maximum voltage drop in the case of different geometric arrangements of the pads supplying power to the chip. These include the square or Manhattan power pad arrangement, which currently predominates, as well as equilateral triangular and hexagonal arrangements. In agreement with the findings in the literature and with physical and SPICE models, the equilateral triangular power pad arrangement is found to minimize the maximum voltage drop. This headline finding is a consequence of relatively simple formulas for the voltage drop, with explicit error bounds, which are established using complex analysis techniques, and elliptic functions in particular.

Sistema d'Informació Geogràfica de Distribució d'Aigües

En aquest projecte es fa la implamantació d'un sistema d'informació geogràfica per la xarxa de distribució d'aigües de la població Bell-lloc d'Urgell. A més a més de tenir digitalitzada tota la zarza, s'incorpora un sistema de gestió, control i seguiment d'avaries.

Introducció als Sistemes d´Informació Geogràfica i creació d´una base de dades dels elements d´una xarxa de distribució d´aigua potable.

Aquest treball és una introducció als sistemes d'informació geogràfica, que consisteix en una breu descripció dels aspectes fonamentals dels sistemes d'informació geogràfica i en la creació d'una base de dades dels elements d'una xarxa de distribució d'aigua potable.

Anàlisi i redisseny de la xarxa de distribució d’ aigua potable a alta pressió de Santa Cristina d’ Aro.

En el present treball es realitza un estudi hidràulic i de qualitat de les aigües de la xarxa municipal per tal d’analitzar en primer lloc el seu estat actual i proposar posteriorment una sèrie d’actuacions de millora. Això s’ha desenvolupat amb l’ajuda d’un programa de simulació de xarxes hidràuliques i de qualitat, en ser l’estudi d’una elevada envergadura, que feia inviable l’estudi empíric de la instal•lació. El simulador utilitzat ha estat l’EPANET, el qual va estar elaborat per la NATIONAL RISK MANAGEMENT RESEARCH LABORATORY de Cincinatty, als Estats Units i traduït a l’espanyol pel grup REDHISP Inst. Ingenieria del agua y M.A. de la Universitat Politècnica de València

A hybrid method for sag source location in power network

The work presented in this paper belongs to the power quality knowledge area and deals with the voltage sags in power transmission and distribution systems. Propagating throughout the power network, voltage sags can cause plenty of problems for domestic and industrial loads that can financially cost a lot. To impose penalties to responsible party and to improve monitoring and mitigation strategies, sags must be located in the power network. With such a worthwhile objective, this paper comes up with a new method for associating a sag waveform with its origin in transmission and distribution networks. It solves this problem through developing hybrid methods which hire multiway principal component analysis (MPCA) as a dimension reduction tool. MPCA reexpresses sag waveforms in a new subspace just in a few scores. We train some well-known classifiers with these scores and exploit them for classification of future sags. The capabilities of the proposed method for dimension reduction and classification are examined using the real data gathered from three substations in Catalonia, Spain. The obtained classification rates certify the goodness and powerfulness of the developed hybrid methods as brand-new tools for sag classification

Organizational Choice and Environmental Change

We explain the choice between franchising and vertical integration by estimating a model of relative performance in a sample of 250 Spanish car distributors, controlling for self-selection and including environmental factors. The method allows us to estimate performance counterfactuals. Organizational choice seemingly aims to contain moral hazard for both distributors and manufacturers but it is subject to start-up constraints and switching costs. While the market for franchises remained underdeveloped, information asymmetries led to the opening of integrated outlets. Their subsequent conversion into franchised outlets probably involved prohibitive transaction costs. Consequently, they performed worse than would have been expected had they been independent, as confirmed by the systematic improvement observed when they were in fact converted. The timing of such conversions suggests that switching costs were prohibitive until firms developed a substantial cushion of temporary contracts, previously forbidden by regulation.

Institutional constraints on organizations: The case of Spanish car dealerships

We study the effect of organizational choice and institutions on the performance ofSpanish car dealerships. Using outlet-level data from 1994, we find that verticallyintegrateddealerships showed substantially lower labor productivity, higher labor costs andlower profitability than franchised ones. Despite these gaps in performance, no verticallyintegratedoutlet was separated until 1994, yet the few outlets that were eventuallyseparated systematically improved their performance. We argue that the conversion ofintegrated outlets into franchised ones involved significant transaction costs, due to aninstitutional environment favoring permanent, highly-unionized employment relations. Inline with this argument, we find that the observed separations occurred in distributionnetworks that underwent marked reductions in worker unionization rates, following thelegalization of temporary labor contracts.

¿Turnos o demanda? En el proyecto de redes de distribución de riego a presión

Actualmente vuelve a ser viable la organización mediante turnos de redes de distribución de riego a presión gracias al desarrollo de sistemas de automáticos de telegestión. La organización por turnos supone una disminución de los caudales en la red y el consiguiente ahorro económico. En la comunicación se presentan diversas expresiones sencillas para calcular la disminución relativa de caudales conseguida mediante la organización por turnos respecto a la demanda. Dicha disminución depende del número de hidrantes abastecidos por un tramo y de la probabilidad de que los hidrantes estén abiertos. Se ha contrastado los resultados de las expresiones propuestas con datos de proyecto y se consiguen buenos ajustes. El ahorro económico obtenido con la organización por turnos respecto a la demanda se puede estimar entre un 26 y un 49 % el ahorro medio de caudales.

Molecular dynamics simulation of the spherical electrical double layer of a soft nanoparticle. Effect of the surface and counterion valence

Molecular dynamics simulations were performed to study the ion and water distribution around a spherical charged nanoparticle. A soft nanoparticle model was designed using a set of hydrophobic interaction sites distributed in six concentric spherical layers. In order to simulate the effect of charged functionalyzed groups on the nanoparticle surface, a set of charged sites were distributed in the outer layer. Four charged nanoparticle models, from a surface charge value of −0.035 Cm−2 to − 0.28 Cm−2, were studied in NaCl and CaCl2 salt solutions at 1 M and 0.1 M concentrations to evaluate the effect of the surface charge, counterion valence, and concentration of added salt. We obtain that Na + and Ca2 + ions enter inside the soft nanoparticle. Monovalent ions are more accumulated inside the nanoparticle surface, whereas divalent ions are more accumulated just in the plane of the nanoparticle surface sites. The increasing of the the salt concentration has little effect on the internalization of counterions, but significantly reduces the number of water molecules that enter inside the nanoparticle. The manner of distributing the surface charge in the nanoparticle (uniformly over all surface sites or discretely over a limited set of randomly selected sites) considerably affects the distribution of counterions in the proximities of the nanoparticle surface.

Choosing hybrid organizations for local services delivery : An empirical analysis of partial privatization

The empirical literature about factors explaining local government delivery choices has traditionally focused the attention on the public or private production dilemma. However, hybrid organizational forms such as mixed public-private firms are increasingly used in several European countries. This paper makes use of survey data from Spanish municipalities to examine motivations of local governments for engaging in hybrid organizational forms. Data refer to two very relevant local services: water distribution and solid waste collection. The empirical analysis indicates that the use of mixed firms emerge as a type of pragmatically based ‘third way’ between pure public and pure private production. Indeed, local governments make use of mixed firms when cost considerations (scale economies, transaction costs and soon), financial constraints and private interests exert contradictory pressures. On the contrary, political and ideological factors do not play any significant role on the local government decision of engaging or not in joint ventures with private partners.

Local privatization, intermunicipal cooperation, transaction costs and political interests: Evidence from Spain

Several empirical studies have analyzed the factors that influence local privatization. Variables related to fiscal stress, cost reduction, political processes and ideological attitudes are the most common explanatory variables used in these studies. In this paper, we add to this literature by examining the influence of transaction costs and political factors on local governments’ choices through new variables. In addition to this, we consider the role of additional aspects, such as intermunicipal cooperation as a potential alternative to privatization in order to exploit scale economies or scope economies. We consider two relevant services: solid waste collection and water distribution. Results from our estimates show that privatization (that is, contracting out to a private firm) is less common for water distribution than for solid waste collection. Higher transaction costs in water distribution are consistent with this finding. Furthermore, we find that municipalities with a conservative ruling party privatize more often regardless of the ideological orientation of the constituency. This shows that those political interests able to influence local elections are more important in determining the form of delivery than is the basic ideological stance of the constituency. Finally, we find that intermunicipal cooperation is an alternative to local privatization.

A quality-based cost distribution charging scheme for QoS multicast networks

This paper presents a new charging scheme for cost distribution along a point-to-multipoint connection when destination nodes are responsible for the cost. The scheme focus on QoS considerations and a complete range of choices is presented. These choices go from a safe scheme for the network operator to a fair scheme to the customer. The in-between cases are also covered. Specific and general problems, like the incidence of users disconnecting dynamically is also discussed. The aim of this scheme is to encourage the users to disperse the resource demand instead of having a large number of direct connections to the source of the data, which would result in a higher than necessary bandwidth use from the source. This would benefit the overall performance of the network. The implementation of this task must balance between the necessity to offer a competitive service and the risk of not recovering such service cost for the network operator. Throughout this paper reference to multicast charging is made without making any reference to any specific category of service. The proposed scheme is also evaluated with the criteria set proposed in the European ATM charging project CANCAN