The interactions between national systems and sectoral patterns of innovation

Do national and sectoral innovation systems interact with each other? The paper explores this unexplored question by carrying out a cross-sector cross-country analysis of European systems of innovation in the 1990s. The empirical study takes Pavitt’s (Res Policy 13:343–373, 1984) taxonomy as a starting point, and it investigates the cross-country variability of Pavitt’s sectoral patterns of innovation. The analysis leads to three main results. First, the various technological trajectories show large differences across countries, due to the influence of national innovation systems. Second, there is evidence that the interaction between national systems and sectoral patterns of innovation constitutes an independent source of variability in the sample. Third, the analysis leads to the identification of eight sector- and country-specific technological trajectories in European manufacturing industries, and, based on that, proposes a refinement of Pavitt’s taxonomy. The refined taxonomy, in a nutshell, suggests that sectoral systems must be supported by and interact with their respective national systems in order to become industrial leaders.     

Stalling innovation of Cognitive Radio: The case for a dedicated frequency band

After more than a decade of frantic R&D efforts, Cognitive Radio (CR) technology continues to fail to pass the first developmental milestone of a working prototype, suggesting that the CR innovation process may be stalling. This paper analyzes possible reasons for this situation from the perspective of innovation management and economics. The CR innovation process has developed in a complex environment shaped by a combination of technology-push and market-pull forces. This paper shows that this process is being stifled by two barriers emerging from the current reliance of CR technology on opportunistic dynamic spectrum access as the sole means for entry into the wireless market. The technology-push is affected by the barrier of technological complexities linked to the requirement to protect highly sensitive incumbent systems. The market-pull forces are being negated by market lock-in and a strong status quo of well-established wireless players. This paper argues that overcoming these barriers and revitalizing the practical development of CR could be possible with the aid of light-touch governmental intervention. This could take the form of designating a dedicated CR band, which would benefit CR through less strict spectrum access requirements. A vibrant cognitive environment could flourish in this type of band, supporting CR innovation.     

Consistent High-precision Volatility from High-frequency Data

Estimates of daily volatility are investigated. Realized volatility can be computed from returns observed over time intervals of different sizes. For simple statistical reasons, volatility estimators based on high-frequency returns have been proposed, but such estimators are found to be strongly biased as compared to volatilities of daily returns. This bias originates from microstructure effects in the price formation. For foreign exchange, the relevant microstructure effect is the incoherent price formation, which leads to a strong negative first-order autocorrelation ρ(1)≃40 per cent for tick-by-tick returns and to the volatility bias. On the basis of a simple theoretical model for foreign exchange data, the incoherent term can be filtered away from the tick-by-tick price series. With filtered prices, the daily volatility can be estimated using the information contained in high-frequency data, providing a high-precision measure of volatility at any time interval.
(J.E.L.: C13, C22, C81).     

Precautionary principle as a rule of choice with optimism on windfall gains and pessimism on catastrophic losses

The paper investigates a decision-making process involving both risk and ambiguity. Differently from existing papers [Basili, M., Chateauneuf, A., Fontini, F., 2005. Choices under ambiguity with familiar and unfamiliar outcomes, Theory and Decision 58, 195-207; Chichilnisky, G., 2000. Axiomatic approach to choice under uncertainty with catastrophic risks. Resources and Energy Economics 22, 221-231; Chichilnisky, G., 2002. In: El-Shaarawi, A.,H., Piegorsch, W.W. (Eds.), Catastropic Risks. Encyclopedia of Environmetrics, vol. 1. John Wiley & Sons, Ltd, Chichester, UK, pp. 274-279], we assume that, in a Choquet Expected Utility framework, the decision-maker is pessimistic with respect to unfamiliar (catastrophic) losses, optimistic with respect to unfamiliar (windfall) gains and ambiguity-neutral with respect to the familiar world. A representation of the decision-maker's choice is obtained that mimics the Restricted Bayes-Hurwicz Criterion. In this way a characterization of the Precautionary Principle is introduced for decision-making processes under ambiguity with catastrophic losses and/or windfall gains.     

Technology Gap and Cumulative Growth: Models and outcomes

Addressing the question of why productivity growth rates differ between countries from a disequilibrium standpoint, the paper explores the possibility of combining in a single formalisation two different but complementary theories of technical change and macroeconomic growth--namely the Kaldorian idea of cumulative causation and the technology-gap approach to economic growth. In order to investigate the complementarities between these two approaches, a two-country macroeconomic model of technology-gap and cumulative growth is presented. The analytical solutions of the model for the growth rates of productivity and demand, and the dynamics of the technology-gap show the existence of a large set of possible outcomes: the follower country can fall behind, partly or totally catch up, or overtake the leader. Moreover, even if the follower is able to close the technology-gap, it will not necessarily be able to close the growth rate differential. The empirical evidence on the experience of 26 OECD countries during 1991-99 shows the relevance of the model for explaining the recent performance of technological activities and productivity growth.     

A non-parametric statistical model for the control of Italian insurance companies

The problem of evaluating the solvency of insurance companies is tackled through the use of a non-parametric statistical model, constructed using decision-tree techniques. The model is tested on a sample of Italian non-life insurance companies and its performance over the test period compared with those of linear and quadratic parametric models.

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Riassunto Il problema della valutazione della solvibilità delle imprese di assicurazione è affrontato con l'impiego di un modello statistico non parametrico, costruito con le tecniche degli alberi delle decisioni. Viene proposta una sperimentazione del modello su un campione di imprese assicuratrici italiane operanti nei rami nonvita ed effettuata una analisi comparata intertemporale con gli standards di efficienza registrati su modelli parametrici lineare e quadratico.

     

Arbitrage, linear programming and martingales¶in securities markets with bid-ask spreads

In a general, finite-dimensional securities market model with bid-ask spreads, we characterize absence of arbitrage opportunities both by linear programming and in terms of martingales. We first show that absence of arbitrage is equivalent to the existence of solutions to the linear programming problems that compute the minimum costs of super-replicating the feasible future cashflows. Via duality, we show that absence of arbitrage is also equivalent to the existence of underlying frictionless (UF) state-prices. We then show how to transform the UF state-prices into state-price densities, and use them to characterize absence of arbitrage opportunities in terms of existence of a securities market with zero bid-ask spreads whose price process lies inside the bid-ask spread. Finally, we argue that our results extend those of Naik (1995) and Jouini and Kallal (1995) to the case of intermediate dividend payments and positive bid-ask spreads on all assets.     

Sectoral productivity trends: convergence islands in oceans of non-convergence

Growth theory argues that thresholds can lead to multiple growth regimes, which are reflected in heterogeneous patterns of cross-country convergence and divergence. We study sectoral convergence patterns by using a new longitudinal sectoral database for 65 developed and developing countries. We employ an econometric method, quantile smoothing splines, which explicitly allows for identification of parameter heterogeneity both with regard to initial conditions (X-heterogeneity) and growth performances (Y-heterogeneity). Findings suggest that convergence is rather the exception than the rule.