5,492 research outputs found
Improving Third-Party Relaying for LTE-A: A Realistic Simulation Approach
In this article we propose solutions to diverse conflicts that result from
the deployment of the (still immature) relay node (RN) technology in LTE-A
networks. These conflicts and their possible solutions have been observed by
implementing standard-compliant relay functionalities on the Vienna simulator.
As an original experimental approach, we model realistic RN operation, taking
into account that transmitters are not active all the time due to half-duplex
RN operation. We have rearranged existing elements in the simulator in a manner
that emulates RN behavior, rather than implementing a standalone brand-new
component for the simulator. We also study analytically some of the issues
observed in the interaction between the network and the RNs, to draw
conclusions beyond simulation observation.
The main observations of this paper are that: ) Additional time-varying
interference management steps are needed, because the LTE-A standard employs a
fixed time division between eNB-RN and RN-UE transmissions (typical relay
capacity or throughput research models balance them optimally, which is
unrealistic nowadays); ) There is a trade-off between the time-division
constraints of relaying and multi-user diversity; the stricter the constraints
on relay scheduling are, the less flexibility schedulers have to exploit
channel variation; and ) Thee standard contains a variety of parameters
for relaying configuration, but not all cases of interest are covered.Comment: 17 one-column pages, 9 figures, accepted for publication in IEEE ICC
2014 MW
Efficiency in the management of urban water services. What have we learned after four decades of research?
The analysis of efficiency in the management of urban water services offers valuable information both for the managers of this service and for public bodies in order to introduce improvements in business practices and in the design of public policies. Since the pioneering study carried out by Ford and Wardford (1969), there have been many attempts to follow this line of research. Due to the importance of the subject and the volume of publications in this field, we believe it is necessary to provide a balance of the work carried out over the last four decades. In this overview, we look at the main questions which have arisen over this period, we provide a synthesis of the results obtained and, finally, we point out some challenges for future research.Water utilities; Efficiency; Firm behaviour; Water
Can we be satisfied with our football team? Evidence from spanish professional football.
This paper assesses the sporting performance of Spanish professional football teams at competition level, namely, League, Kingâs Cup and European competitions (Champions League and UEFA Cup). Then, the gap between the result obtained by a team in a given competition and that expected according to its potential is used as a proxy of the degree of satisfaction that fans should feel: the narrower the gap the greater the level of satisfaction. Regarding methodology, Data Envelopment Analysis techniques and directional distance functions are used. Results reveal that most teams perform rather differently across competitions, the lower average performance corresponding to the Kingâs CupSpanish football League; specific-competition performance; Data Envelopment Analysis.
DOES SERVICE QUALITY MATTER IN MEASURING PERFORMANCE OF WATER UTILITIES?
Quality is a dimension of water services that has been repeatedly omitted in the study of performance of water utilities. In this paper, we make use of Data Envelopment Analysis techniques (DEA) to compute both conventional quantity-based and quality-adjusted indicators of technical efficiency for a sample of Spanish water utilities. The key assumptions are that a lack of quality (bad quality) can be regarded as a bad output, and the existence of a trade-off between quantity and quality. Our main results indicate that quality matters in measuring technical performance, the difference between conventional and quality-adjusted evaluations representing the opportunity cost of maintaining quality. Averages and distribution functions significantly differ between both assessments of performance, although water utilities do not seem to rank differently.water utilities; quality; Data Envelopment Analysis.
Standardization Framework for Sustainability from Circular Economy 4.0
The circular economy (CE) is widely known as a way to implement and achieve sustainability, mainly due to its contribution towards the separation of biological and technical nutrients under cyclic industrial metabolism. The incorporation of the principles of the CE in the links of the value chain of the various sectors of the economy strives to ensure circularity, safety, and efficiency. The framework proposed is aligned with the goals of the 2030 Agenda for Sustainable Development regarding the orientation towards the mitigation and regeneration of the metabolic rift by considering a double perspective. Firstly, it strives to conceptualize the CE as a paradigm of sustainability. Its principles are established, and its techniques and tools are organized into two frameworks oriented towards causes (cradle to cradle) and effects (life cycle assessment), and these are structured under the three pillars of sustainability, for their projection within the proposed framework. Secondly, a framework is established to facilitate the implementation of the CE with the use of standards, which constitute the requirements, tools, and indicators to control each life cycle phase, and of key enabling technologies (KETs) that add circular value 4.0 to the socio-ecological transition
Catalogación y anålisis de los sistemas de envolvente neumåtica, a través del estudio de sus principales paråmetros cualitativos
El diseño de sistemas neumĂĄticos como envolvente arquitectĂłnica ha experimentado un importante desarrollo, desde que a principios del s.XX las nuevas necesidades militares, sociales y econĂłmicas requirieran nuevos sistemas para la cubriciĂłn de grandes luces, con un rĂĄpido y fĂĄcil montaje. Sin embargo, los mĂșltiples proyectos y experiencias, se han desarrollado sin una lĂnea constante de documentaciĂłn y catalogaciĂłn. Su revisiĂłn histĂłrica y crĂtica, a travĂ©s de artĂculos y publicaciones especializadas, ha mantenido un ciclo paralelo al interĂ©s global mostrado por este tipo de sistemas constructivos; apareciendo picos de mĂĄxima desarrollo, como el de los años setenta, y valles de escasa documentaciĂłn como el de dĂ©cadas posteriores. La investigaciĂłn ha tenido como objetivo la realizaciĂłn de una nueva revisiĂłn histĂłrica y crĂtica de esta todavĂa âjovenâ tecnologĂa, complementando los periodos de menor catalogaciĂłn y permitiendo establecer los condicionantes principales y los puntos de afianzamiento y de inflexiĂłn, desarrollados en el ĂĄmbito de los sistemas de envolvente neumĂĄtica arquitectĂłnica. La metodologĂa de anĂĄlisis se ha focalizado en la localizaciĂłn y documentaciĂłn de aquellos proyectos, tanto construidos como conceptuales, cuyas propiedades cualitativas hayan supuesto una especial innovaciĂłn en el ĂĄmbito de las tecnologĂas de envolvente neumĂĄtica. De modo que sobre cada una de las estrategias catalogadas, se ha procedido al estudio pormenorizado de sus parĂĄmetros morfolĂłgicos, funcionales, constructivos, energĂ©ticos y medioambientales. La metodologĂa de organizaciĂłn de datos, se ha coordinado a travĂ©s de la realizaciĂłn de una base de datos de carĂĄcter interactiva y abierta, facilitanto tanto el estudio individualizado de cada una de las propuestas, como el anĂĄlisis comparativo de los diferentes proyectos, en funciĂłn de los diferentes parĂĄmetros y subparĂĄmetros de caracterizaciĂłn. La catalogaciĂłn de mĂĄs de 660 estrategias, ha permitido el estudio comparativo y evolutivo de las principales tipologĂas neumĂĄticas; a travĂ©s de un sistema organizativo de cĂłdigo abierto, que ha facilitado una lectura de resultados no lineal, interactiva y dinĂĄmica
Performance and ownership in the governance of urban water
In this paper the differences in terms of performance between public and the private governance in urban water management are investigated. A statistical ranking is implemented to determine programmatic efficiency differences in DEA, using an incomplete panel data that gathers information on 20 water utilities in Andalusia, in Southern Spain. In the model, labour and operational costs are considered as inputs. The volume of revenue water, the number of connections and the network length are used as outputs. The analysis indicates that private management is more efficient. The efficiency indicators adjusted by a variable related to quality are estimated and demonstrate that privatization of the service does not mean any loss in terms of quality. However, there are no significant differences between both types of management including as a desirable input hydraulic yield as a proxy of the degree of network renovation. A lower hydraulic efficiency in private management would suggest that the need to make significant investments could be an important factor when making the decision to privatize the management of the urban water service: Water supply; Management; Local government;
The importance of time in referee home bias due to social pressure. Evidence from Spanish football
This paper analyses referee home bias due to social pressure with data from the matches played in the First Division of the Spanish football league between the 2002/03 and 2009/10 seasons. Finally, our main conclusion is that the time the referee has to make a decision does affect the final outcome; while there is no referee home bias when a free kick is awarded, in the case of booking players, when the referee has more time to make a decision, social pressure can influence the final outcome in favour of the home team.Social pressure; crowd effect; referee home bias; sports economics.
The cyclical trend of local public service governance: evidence from urban water management in Spain
The level of public and private involvement in economic activity in societies has changed over time. One may talk about the existence of a cyclical trend in which the most important periods of public governance are replaced by periods in which private management dominates the situation. This phenomenon may also be observed in local areas. Some authors have pointed out the existence of an alternation in the provision of municipal services, resulting in periods dominated by governance compared to other stages dominated by private management. In order to illustrate this cyclical trend at local level, this paper intends to analyze the evolution of the governance of the Spanish water supply since the mid-nineteenth century to the present day. Recent evidence from the industry suggests the possibility that we may currently be witnessing a further change in the trend.: Local Government, urban water supply, privatization, municipalization
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