A note on how to measure hubbing practices in airline networks

Benefits and costs associated to hubbing practices of airlines are still subject to much debate. In the previous literature, some standard spatial concentration indices have been proposed to measure it. However, we show that these indices are “ill-defined” because they do not take into account the salient characteristic of hubbing: connecting passengers. The purpose of this research is to present a new methodology which avoids the pitfalls of other methods. Our new methodology also analyzes the level of concentration of the connecting passengers studying two different dimensions: hub airports and routes. Finally, we apply our methodology to some US carriers.     

ESTIMATION OF VALUE AT RISK AND RUIN PROBABILITY FOR DIFFUSION PROCESSES WITH JUMPS

In this paper we give upper bounds for both the Value at Risk   VaR _α,  0 < α < 1  , and for ruin probabilities associated with the supremum of a process driven by a Brownian motion and a compound Poisson process. We obtain lower bounds for the same Value at Risk, and for different cases we discuss the behavior of the bounds for small α. We prove our bounds are asymptotically optimal, as α tends to zero. The ruin probabilities obtained are related to other bounds found in recent literature.     

Perception evaluation kit: a case study with materials and learning styles

International Journal of Technology and Design Education - Materials are elements that configure our built environment and are key components in design and engineering education. This research aims...     

Pseudo empirical likelihood method in the presence of missing data

In this paper, we propose an estimator for the population mean when some observations on the study and auxiliary variables are missing from the sample. The proposed estimator is valid for any unequal probability sampling design, and is based upon the pseudo empirical likelihood method. The proposed estimator is compared with other estimators in a simulation study.     

Is the leadership style important in R&D departments in Spanish industrial companies? An empirical analysis

This paper aims to thoroughly look into the effects of the differences between the diverse leadership styles on innovative outputs (intensive, efficient and eco-efficient) in Spanish industrial companies. A questionnaire for the factories was sent and was received between the months of September 2013 and June 2014. A total of 142 valid questionnaires were received. Several regression models were used in the empirical analysis. The results show that charismatic leadership positively induces an intensive innovative output, at the same time as it improves firms’ eco-efficient innovative output. Likewise, the individualised consideration that characterises transformational leadership makes this leadership style produce positive results on the whole group of innovative outputs considered. At the other end of the leadership spectrum, the transactional style causes negative effects on the relationship between innovative activity and innovative outputs, and more specifically, on the efficient innovative output.     

On the impact of leverage constraints on asset prices and trading volume

Abstract. Researchers have used stylized facts on asset prices and trading volume in stock markets (in particular, the mean reversion of asset returns and the correlations between trading volume, price changes and price levels) to support theories where agents are not rational expected utility maximizers. This paper shows that this empirical evidence is in fact consistent with a standard infinite horizon – perfect information – expected utility economy where some agents face leverage constraints similar to those found in todays financial markets. In addition, and in sharp contrast to the theories above, we explain some qualitative differences that are observed in the price-volume relation on stock and on futures markets. We consider a continuous-time economy where agents maximize the integral of their discounted utility from consumption under both budget and leverage constraints. Building on the work by Vila and Zariphopoulou (1997), we find a closed form solution, up to a negative constant, for the equilibrium prices and demands in the region of the state space where the constraint is non-binding. We show that, at the equilibrium, stock holdings volatility as well as its ratio to stock price volatility are increasing functions of the stock price and interpret this finding in terms of the price-volume relation. We would like to thank the editor and two anonimous referees for valuable substantive comments. Our gratitude also to Franklin Allen, Kerry Back, Domenico Cuoco, Xavier Freixas, Sanford Grossman, Michel Habib, Lutz Hendricks, Richard Kihlstrom, Fernando Restoy, Mary Thomson, Jean-Luc Vila, participants to seminars at Birkbeck College, Carnegie-Mellon, Columbia, ESSEC, HEC, IAE, INSEAD, London Business School, London School of Economics, McGill, Michigan, National University of Singapore, Pompeu Fabra, North Carolina, Washington-St-Louis, Wharton, the Jornadas de Economía Financiera BBV, and the Meetings of the Society for Economic Dynamics and Control and the American Finance Association. Special thanks are due to Süleyman Basak for his enthusiastic support and many helpful suggestions. The usual disclaimer applies. We gratefully acknowledge the support of the BBV and Caja de Madrid Foundations and CREF (both authors) and of the Spanish Ministry of Education under DGICYT grant no. PB93-0388 (first author).     

ICP 2005 Construction Prices: Are They Underestimated in Developing Countries?

Construction prices are lower in developing countries in ICP 2005, which has raised these countries' capital/output ratio in Penn World Tables 7 and 8 and affected growth analyses. We estimate the Colombia/U.S. price ratio for office and apartment buildings in 2005 as a test of the validity of the ICP 2005 methodology for estimating these prices. Our estimate of the Colombia/U.S. price ratio is almost twice the ICP 2005 estimate. We confirm the validity of our results by estimating the cost of constructing office and apartment buildings using 2005 prices for construction materials, equipment, and labor in both countries.     

Patents,technological inputs and spillovers among regions

This article analyses the importance of different technological inputs (R&D and human capital) and different spillovers in explaining the differences in patenting among Spanish regions in the period 1986 to 2003. The analysis is based on the estimation of a knowledge production function. A region's own R&D activities and human capital are observed to have a positive significant effect on innovation output, measured by the number of patents. R&D spillovers weighted by the distance and the volume of trade flows between regions cause positive effects on a region's patents. However, distance matters more than the intensity of trade flows and the R&D spillover effects between regions are bounded: spillovers from closer regions perform better than spillovers from distant regions. On the opposite side, human capital spillovers do not cause any effect outside the region itself.