1,922 research outputs found
Testing for Economies of Scope in European Railways: An Efficiency Analysis
In this paper, we conduct a pan-European effciency analysis to investigate the performance of European railways with a particular focus on economies of vertical integration. We test the hypothesis that integrated railways realize economies of scope and, thus, produce railway services with a higher level of effciency. To determine whether joint or separate production is more effcient, we apply a Data Envelopment Analysis super-effciency bootstrapping model which relates the ef- ficiency for integrated production to a reference set consisting of separated firms which use a dierent production technology. We find that for a majority of European railways economies of scope exist.Efficiency, Vertical Integraton, Railway Industry
Economies of Scope in European Railways: An Efficiency Analysis
In the course of railway reforms in the end of the last century, national European governments, as well the EU Commission, decided to open markets and to separate railway networks from train operations. Vertically integrated railway companies – companies owning a network and providing transport services – argue that such a separation of infrastructure and operations would diminish the advantages of vertical integration and would therefore not be suitable to raise economic welfare. In this paper, we conduct a pan-European analysis to investigate the performance of European railways with a particular focus on economies of vertical integration. We test the hypothesis that integrated railways realise economies of joint production and, thus, produce railway services on a higher level of efficiency. To determine whether joint or separate production is more efficient we apply a Data Envelopment Analysis super-efficiency bootstrapping model which relates the efficiency for integrated production to a virtual reference set consisting of the separated production technology. Our findings are that in a majority of European Railway companies exist economies of scope.efficiency, vertical integration, railway industry
Economies of Scope in European Railways: An Efficiency Analysis
In the course of railway reforms at the end of the last century, European na- tional governments, as well the EU Commission, decided to open markets and to separate railway networks from train operations. Vertically integrated railway com- panies argue that such a separation of infrastructure and operations would diminish the advantages of vertical integration and would therefore not be suitable to raise economic welfare. In this paper, we conduct a pan-European analysis to investi- gate the performance of European railways with a particular focus on economies of scope associated with vertical integration. We test the hypothesis that integrated railways realize economies of joint production and, thus, produce railway services on a higher level of efficiency. To determine whether joint or separate production is more efficient we apply an innovative Data Envelopment Analysis super-efficiency bootstrapping model which relates the efficiency for integrated production to a vir- tual reference set consisting of the separated production technology and which is applicable to other network industries as energy and telecommunication as well. Our findings are that for a majority of European Railway companies economies of scope exist.Efficiency, Vertical Integration, Railway Industry
Efficiency effects of quality of service and environmental factors: experience from Norwegian electricity distribution
Since the 1990s, efficiency and benchmarking analysis has increasingly been used in network utilities research and regulation. A recurrent concern is the effect of environmental factors that are beyond the influence of firms (observable heterogeneity) and factors that are not identifiable (unobserved heterogeneity) on measured cost and quality performance of firms. This paper analyses the effect of geographic and weather factors and unobserved heterogeneity on a set of 128 Norwegian electricity distribution utilities for the 2001-2004 period. We utilize data on almost 100 geographic and weather variables to identify real economic inefficiency while controlling for observable and unobserved heterogeneity. We use the factor analysis technique to reduce the number of environmental factors into few composite variables and to avoid the problem of multicollinearity. We then estimate the established stochastic frontier models of Battese and Coelli (1992; 1995) and the recent true fixed effects models of Greene (2004; 2005) without and with environmental variables. In the former models some composite environmental variables have a significant effect on the performance of utilities. These effects vanish in the true fixed effects models. However, the latter models capture the entire unobserved heterogeneity and therefore show significantly higher average efficiency scores.Efficiency; Quality of service; Input distance function; Stochastic frontier analysis
Seismotectonic study of the Fergana region (Southern Kyrgyzstan): distribution and kinematics of local seismicity
We present new seismicity and focal-mechanism data for the Fergana basin and surrounding mountain belts in western Kyrgyzstan from a temporary local seismic network. A total of 210 crustal earthquakes with hypocentral depths shallower than 25 km were observed during a 12-month period in 2009/2010. The hypocenter distribution indicates a complex net of seismically active structures. The seismicity derived in this study is mainly concentrated at the edges of the Fergana basin, whereas the observed rate of seismicity within the basin is low. The seismicity at the dominant tectonic feature of the region, the Talas-Fergana fault, is likewise low, so the fault seems to be inactive or locked. To estimate the uncertainties of earthquake locations derived in this study, a strong explosion with known origin time and location is used as a ground truth calibration event which suggests a horizontal and vertical accuracy of about 1 km for our relocations. We derived 35 focal mechanisms using first motion polarities and retrieved a set of nine moment tensor solutions for earthquakes with moment magnitude (Mw) ranging from 3.3 to 4.9 by waveform inversion. The solutions reveal both thrust and strike-slip mechanisms compatible with a NW-SE direction of compression for the Fergana region. Two previously unknown tectonic structures in the Fergana region could be identified, both featuring strike-slip kinematics. The combined analysis of the results derived in this study allowed a detailed insight into the currently active tectonic structures and their kinematics where little information had previously been available
Model Studies On The Interactions Among Carbon Substrates, Bacteria And Consumers In A Salt-Marsh Estuary
We have developed a lagrangian computer simulation model to investigate the interactions between dissolved and particulate carbon-substrates of detrital (vascular plants) and phytoplankton origin, microbes attached and free-living in the water column, and consumers of these substrates for a specific estuarine water body: the Duplin River, Sapelo Island, Georgia. Model simulation experiments were directed toward investigating the potential for both carbon resource and heterotrophic grazing as controls on free-living and particle-attached bacterial densities. Given available information from the literature and our own work, we present simulations of the model that approximate what one generally finds in this estuary during summer relative to the dynamics of particulate organic carbon (paC), dissolved organic carbon (DOC), free-living bacteria and microconsumers. Predicted dynamics of the bacteria were insensitive to macroconsumer grazing but highly sensitive to the parameter values governing microconsumer grazing rates and metabolism. Within reasonable constraints of the parameter values used, however, we were unable to reduce the predicted densities of particle-attached bacteria by manipulation of either resource (carbon) availability or grazing pressures. We propose several alternate hypotheses that might explain this discrepancy between model results and what is generally reported for natural systems
Verbundvorteile für den Börsengang der Deutschen Bahn ausreichend berücksichtigt?
Die aktuelle Diskussion um den Umfang des Börsengangs der Deutschen Bahn – unter Einbeziehung des Schienennetzes oder nicht – konzentriert sich im wesentlichen auf Fragen der Wettbewerbswirkung und der zukünftigen Belastung des Staatshaushaltes. Eventuelle Vorteile der bestehenden Organisationsform der Deutschen Bahn, also eines vertikal integrierten Eisenbahnunternehmens, das sowohl den Infrastrukturzugang als auch Transportdienstleistungen anbietet, blieben trotz ihrer Bestätigung in einer Vielzahl theoretischer Analysen weitgehend unberücksichtigt. Die Deutsche Bahn äußerte nun die Befürchtung, daß eine solche Separierung Vorteile der vertikalen Integration (sogenannte Verbundvorteile) vermindern würde und somit nicht geeignet sei, die gesamtgesellschaftliche Wohlfahrt zu erhöhen. In einer paneuropäischen Analyse der Produktivität europäischer Eisenbahnunternehmen wird mit dem Fokus der Untersuchung auf etwaige Verbundvorteile überprüft, ob integrierte Eisenbahnunternehmen eine höhere technische Effizienz aufweisen als vertikal separierte Unternehmen. Dazu wird ein Modell erstellt, das die Effizienz der integrierten Produktionstechnologie im Verhältnis zu einer Referenzgruppe virtueller, aus den separierten Unternehmen konstruierter Beobachtungseinheiten berechnet. Die Ergebnisse weisen auf existierende Verbundvorteile für die Mehrzahl der europäischen Eisenbahnunternehmen hin. Dies sollte in der Entscheidung hinsichtlich des Börsengangs der Deutschen Bahn explizite Berücksichtigung finden.
Verbundvorteile für den Börsengang der Deutschen Bahn ausreichend berücksichtigt?
Die aktuelle Diskussion um den Umfang des Börsengangs der Deutschen Bahn – unter Einbeziehung des Schienennetzes oder nicht – konzentriert sich im wesentlichen auf Fragen der Wettbewerbswirkung und der zukünftigen Belastung des Staatshaushaltes. Eventuelle Vorteile der bestehenden Organisationsform der Deutschen Bahn, also eines vertikal integrierten Eisenbahnunternehmens, das sowohl den Infrastrukturzugang als auch Transportdienstleistungen anbietet, blieben trotz ihrer Bestätigung in einer Vielzahl theoretischer Analysen weitgehend unberücksichtigt. Die Deutsche Bahn äußerte nun die Befürchtung, daß eine solche Separierung Vorteile der vertikalen Integration (sogenannte Verbundvorteile) vermindern würde und somit nicht geeignet sei, die gesamtgesellschaftliche Wohlfahrt zu erhöhen. In einer paneuropäischen Analyse der Produktivität europäischer Eisenbahnunternehmen wird mit dem Fokus der Untersuchung auf etwaige Verbundvorteile überprüft, ob integrierte Eisenbahnunternehmen eine höhere technische Effizienz aufweisen als vertikal separierte Unternehmen. Dazu wird ein Modell erstellt, das die Effizienz der integrierten Produktionstechnologie im Verhältnis zu einer Referenzgruppe virtueller, aus den separierten Unternehmen konstruierter Beobachtungseinheiten berechnet. Die Ergebnisse weisen auf existierende Verbundvorteile für die Mehrzahl der europäischen Eisenbahnunternehmen hin. Dies sollte in der Entscheidung hinsichtlich des Börsengangs der Deutschen Bahn explizite Berücksichtigung finden.
High Performance Green LEDs by Homoepitaxial
This work's objective was the development of processes to double or triple the light output power from green and deep green (525 - 555 nm) AlGaInN light emitting diode (LED) dies within 3 years in reference to the Lumileds Luxeon II. The project paid particular effort to all aspects of the internal generation efficiency of light. LEDs in this spectral region show the highest potential for significant performance boosts and enable the realization of phosphor-free white LEDs comprised by red-green-blue LED modules. Such modules will perform at and outperform the efficacy target projections for white-light LED systems in the Department of Energy's accelerated roadmap of the SSL initiative
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