Simple and Efficient Fully-Functional Succinct Trees

The fully-functional succinct tree representation of Navarro and Sadakane (ACM Transactions on Algorithms, 2014) supports a large number of operations in constant time using $2n+o(n)$ bits. However, the full idea is hard to implement. Only a simplified version with $O(\log n)$ operation time has been implemented and shown to be practical and competitive. We describe a new variant of the original idea that is much simpler to implement and has worst-case time $O(\log\log n)$ for the operations. An implementation based on this version is experimentally shown to be superior to existing implementations

The Designated Hitter Rule and Team Defensive Strategy in Japan’s Professional Baseball Leagues

Economists have debated whether and why the designated hitter (DH) rule in North American major league baseball led to an increase in hit-batsmen. We use data from Japan's professional baseball leagues, the Pacific League (DH rule) and the Central League (no DH rule), to re-examine this question. Initial empirical findings reveal increases in hit-batsmen in the Pacific League after we control for the DH’s effect on team batting performance. After controlling for interactions between pitcher quality and the DH rule, we find that the DH rule induced changes in team defensive strategies and, consequently, an increase in hit-batsmen. Subsequent rule changes reduced the effectiveness of these strategies.

Structural dynamics of shroudless, hollow fan blades with composite in-lays

Structural and dynamic analyses are presented for a shroudless, hollow titanium fan blade proposed for future use in aircraft turbine engines. The blade was modeled and analyzed using the composite blade structural analysis computer program (COBSTRAN); an integrated program consisting of mesh generators, composite mechanics codes, NASTRAN, and pre- and post-processors. Vibration and impact analyses are presented. The vibration analysis was conducted with COBSTRAN. Results show the effect of the centrifugal force field on frequencies, twist, and blade camber. Bird impact analysis was performed with the multi-mode blade impact computer program. This program uses the geometric model and modal analysis from the COBSTRAN vibration analysis to determine the gross impact response of the fan blades to bird strikes. The structural performance of this blade is also compared to a blade of similar design but with composite in-lays on the outer surface. Results show that the composite in-lays can be selected (designed) to substantially modify the mechanical performance of the shroudless, hollow fan blade

Labor Policy and Investment

Policy debates over proposed legislative labor policy changes include contentions that business investment will negatively respond to labor laws that favor labor. Research on labor policy, however, often assumes that investment is fixed. We present a sequential bargaining model in which labor policies that increase labor's bargaining power and reduce management's options during strikes are predicted to reduce investment. Using provincial data on investment for 1967 to 1999, a strike replacement ban and protections for workers who refuse to handle struck work are estimated to reduce new investment, especially within the first few years after the policy change.

Are Good Industrial Relations Good for the Economy?

Using international data, we investigate whether the quality of industrial relations matters for the macro economy. We measure industrial relations inversely by strikes Ð which proxy we cross-check with an industrial relations reputation indicator Ð and our macro performance indicator is the unemployment rate. Independent of the role of other institutions, good industrial relations do seem to matter: greater strike volume is associated with higher unemployment. But these results apply in cross section. Holding country effects constant, the sign of the strikes coefficient is abruptly reversed. Although it does not seem to be the case that the line of causation runs from unemployment to strikes once we control for the endogeneity of strikes, it is also the case that support for the strikes proxy for industrial relations quality is much eroded.strikes, industrial relations quality, unemployment, labor market institutions, cross-country data

Interest Rate Caps Smile Too! But Can the LIBOR Market Models Capture It?

Using more than two years of daily interest rate cap price data, this paper provides a systematic documentation of a volatility smile in cap prices. We find that Black (1976) implied volatilities exhibit an asymmetric smile (sometimes called a sneer) with a stronger skew for in-the-money caps than out-of-the-money caps. The volatility smile is time varying and is more pronounced after September 11, 2001. We also study the ability of generalized LIBOR market models to capture this smile. We show that the best performing model has constant elasticity of variance combined with uncorrelated stochastic volatility or upward jumps. However, this model still has a bias for short- and medium-term caps. In addition, it appears that large negative jumps are needed after September 11, 2001. We conclude that the existing class of LIBOR market models can not fully capture the volatility smileLIBOR market models, volatility smile, interest rate caps

Have industrial relations in the UK really improved?

The number of strikes reported in British industry has been on a downward trend over the past two decades, falling in 1998 to their lowest level since records began. This may indicate that relations within British industry have improved, however, the same period has also witnessed a sharp increase in the number of individual ACAS and employment tribunal cases. We discuss possible reasons for the changes in the patterns of industrial unrest over time and use individual microdata to examine whether the observed decline in strike activity has actually been associated with an improvement in perceptions of workplace industrial relations.Industrial relations; strikes; individual disputes