4,021 research outputs found
GIS-based methodology for evaluating the wind-energy potential of territories: A case study from Andalusia (Spain)
In recent years, Spain, in an effort to meet European Union (E.U.) targets, has been developing different strategies to promote the installation of renewable energy plants. In this regard, evaluating territories to assess their potential and thus identify optimum sites for the installation of energy-generating facilities is a crucial task. This paper presents a comprehensive geographic information system (GIS)-based site-selection methodology for wind-power plants in the province of Córdoba, which has hitherto been regarded as unsuitable for this sort of facility owing to the lack of wind resources. Three scenarios have been set out, each of which presents a different set of restrictions. Scenario 2 applies the most stringent restrictions in the specialized literature, and finds no suitable areas for the installation of wind-energy plants. However, Scenario 1, which applies the least stringent restrictions, and Scenario 3, which applies the same restrictions currently in force for other wind turbines already in operation in Andalusia, have led to the identification of several areas that could a priori be considered suitable and now need more detailed analysis. The results illustrate the convenience of undertaking multiscenario analyses
Can insider power affect employment?.
Do firms reduce employment when their insiders (established, incumbent employees) claim higher wages? The conventional answer in the theoretical literature is that insider power has no influence on employment, provided that the newly hired employees (entrants) receive their reservation wages. The reason given is that an increase in insider wages gives rise to a countervailing fall in reservation wages, leaving the present value of wage costs unchanged. Our analysis contradicts this conventional answer. We show that, in the context of a stochastic model of the labor market, an increase in insider wages promotes firing in recessions, while leaving hiring in booms unchanged. Thereby insider power reduces average employment.Lohnstruktur; Insider-Outsider-Modell; Arbeitsuche; Anspruchslohn; Marktmacht; Theorie;Employment; Wage determination; market power; insiders;
A generic radio channel emulator to evaluate higher layer protocols in a CDMA system
Currently, we are involved in the standardisation process to specify the next mobile system generation. A wideband code division multiple access (WCDMA) system is considered in most of the region versions. It would be very useful to count on a radio channel emulator which allows one to evaluate higher layers protocols within this context. This paper presents a radio channel emulator developed for a code division multiple access (CDMA) based system. Its versatility and low complexity have been exposed, and the validation process to check the model accuracy has also been shown for this system as an example.Peer ReviewedPostprint (published version
A radio channel emulator for WCDMA, based on the hidden Markov model (HMM)
One of the main development and research subjects within the telecommunications area activity is the 3G mobile systems standardisation. The radio access is, of course, the main trouble in mobile systems, so it is important to investigate its implication. This paper describes a radio channel emulator for the UTRA-FDD made, based on the hidden Markov model (HMM). Since a statistical system behaviour is needed to train the HMM, off-line simulations have been made. The results between simulated and emulated statistics are presented. The use of emulation models implies a loss of accuracy with respect to simulation models, but is adequate to operate in real time. Certainly, the main advantage of using HMM in the emulator is the huge reduction in time, resources and effort with regard to a real simulation of the system. The emulator will allow in future works, for fast testing and comparison of several higher layer protocols and error control schemes.Peer ReviewedPostprint (published version
Performance of a linear interference canceller for a ds/cdma synchronous system based on the ekf delay estimator
Since the conventional detector often fails to produce reliable decisions for a CDMA channel, several new multiuser detectors have previously proposed. In the present paper, the authors propose both a simple linear scheme for interference cancellation, which exhibits good performance, and a synchronism scheme based on the extended Kalman filter (EKF) to achieve synchronization among the different users at the base station, for a direct-sequence code-division multiple-access (DS/CDMA) synchronous system. The influence of the synchronism scheme on the performance of the interference canceller is analyzed under Rayleigh multipath fading.Peer ReviewedPostprint (published version
On soft/hard handoff for packet data services in cellular CDMA mobiles systems
Benefits of macrodiversity operation for packet data services in third generation mobile systems are not obvious. Retransmission procedures to enhance link performance and higher downlink bandwidth requirements could question macrodiversity usage. This paper describes a simple methodology to compare soft and hard handoff performance in terms of transmission delay for packet data services. The handover procedures are based exclusively on power criteria and hysteresis margins.Peer ReviewedPostprint (published version
Social History and Cultural History of Women: elements for debate
Este artÃculo hace una reflexión teórica sobre
las categorÃas de análisis y los criterios de
investigación que han primado en las últimas
décadas en las investigaciones sobre la historia
de las mujeres. Se señala en primer lugar
la trayectoria del uso del término género y se
detiene en el de la identidad para criticar la utilización
del mismo resaltando como, si bien en
un principio y, sobre todo, en relación a temas
de creación artÃstica, tuvo una gran utilidad, el
uso abusivo del mismo y la generalización de
su manejo puede resultar ineficaz. Por último
plantea la dicotomÃa entre la historia cultural y
la historia social, decantándose por la segunda
como corriente capaz de retomar la visión generalista
y reivindicativa del feminismoThis article reflects upon categories of analysis
and research criteria used by studies into the
History of Women in recent decades. First,
the focus falls on the evolution of the use of
the term ‘gender’ before similarly reflecting
on the use of term ‘identity’, criticising its
use. In so doing, the article highlights that;
although in principle, and above all in relation
to topics of artistic creation, it use was of
great utility; the abusive use of the term and
the generalisation of its employment may be
ineffective. Finally, the article also deals with
the dichotomy between Cultural and Social
History, suggesting that Social History is a
trend capable of defeating the generalistic
and vindictive vision of Feminis
Multiple slot allocation for voice/data transmission over PRMA++ applied to FRAMES multiple access mode 1
This paper presents some simulation results of PRMA++ for voice and data transmission over a physical air interface platform defined in the ACTS European project FRAMES. Variations on the statistics of speech sources (activity factor, petition rate) are studied and conclusions are obtained for optimal frame dimensioning. For data transmission, a multiple slot allocation scheme is presented and results are shown for different source rates and packet lengths.Peer ReviewedPostprint (published version
El pensamiento de Hannah Arendt, una visión global
Tal i com anuncia el tÃtol, l’article pretén introduir al lector que no coneix a Hannah Arendt en el seu pensament, a través dels seus temes essencials, introduint l’acció i la polÃtica com la dimensió més important de l’acivitat humana, en la mesura que és capaç de crear el món en el que el sentit comú permetrà l’aparició de la llibertat i la responsabilitat; es planteja també, ja dins l’à mbit de la vida contemplativa, on es planteja el judici moral i l’anà lidi de concepte –clau en la nostra autora- de la banalitat del mal, el que obliga a nalitzar el seguiment arendtià del judici a Eichmann i l’anà lisi més general del totalitarisme, fenomen que introduiex les seves arrels i troba la seva explicació en la modernitat. Com a conclusió, s’introduiex la proposta polÃtica de la nostra autora, el republicanisme, forma polÃtica defençada per la nostra autora en la mesura en que l’acció humana permet arribar al consens.Tal como anuncia el tÃtulo, el artÃculo pretender introducir al lector que no conoce a Hannah Arendt en su pensamiento, a través de sus temas esenciales, introduciendo la acción y la polÃtica como la dimensión más importante de la actividad humana, en la medida en que es capaz de crear el mundo en el que el sentido común permitirá la aparición de la libertad y la responsabilidad; se plantea también, ya en el ámbito de la vida contemplativa, las conexiones entre pensamiento, acción y voluntad, que llevan directamente al ámbito de la moralidad, donde se plantea el juicio moral y el análisis del concepto -clave en nuestra autora- de la banalidad del mal, lo que obliga a analizar el seguimiento arendtiano del juicio a Eichmann y el análisis más general del totalitarismo, fenómeno que hunde sus raÃces y halla su explicación en la modernidad. Como conclusión, se introduce la propuesta polÃtica de nuestra autora, el republicanismo, forma polÃtica defendida por nuestra autora en la medida en que en ella la acción humana permite llegar al consenso
- …