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A NONPARAMETRIC ESTIMATOR FOR THE COVARIANCE FUNCTION OF FUNCTIONAL DATA

Published online by Cambridge University Press:  18 November 2014

Alessio Sancetta*
Affiliation:
Royal Holloway University of London
*
*Address correspondence to Alessio Sancetta, Department of Economics, Royal Holloway University of London, Egham TW20 0EX, UK; e-mail: [email protected].

Abstract

Many quantities of interest in economics and finance can be represented as partially observed functional data. Examples include structural business cycle estimation, implied volatility smile, the yield curve. Having embedded these quantities into continuous random curves, estimation of the covariance function is needed to extract factors, perform dimensionality reduction, and conduct inference on the factor scores. A series expansion for the covariance function is considered. Under summability restrictions on the absolute values of the coefficients in the series expansion, an estimation procedure that is resilient to overfitting is proposed. Under certain conditions, the rate of consistency for the resulting estimator achieves the minimax rate, allowing the observations to be weakly dependent. When the domain of the functional data is K(>1) dimensional, the absolute summability restriction of the coefficients avoids the so called curse of dimensionality. As an application, a Box–Pierce statistic to test independence of partially observed functional data is derived. Simulation results and an empirical investigation of the efficiency of the Eurodollar futures contracts on the Chicago Mercantile Exchange are included.

Type
ARTICLES
Copyright
Copyright © Cambridge University Press 2014 

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References

REFERENCES

Almgren, R. (2003) Optimal execution with nonlinear impact functions and trading-enhanced risk. Applied Mathematical Finance 10, 118.CrossRefGoogle Scholar
Almgren, R. & Chriss, N. (2000) Optimal execution of portfolio transactions. Journal of Risk 3, 539.CrossRefGoogle Scholar
Alva, K., Romo, J., & Ruiz, E. (2009) Modelling Intra-Daily Volatility by Functional Data Analysis: An Empirical Application to the Spanish Stock Market. Working paper 09–28, Statistics and Econometrics, Departamento de Estadística, Universidad Carlos III de Madrid.Google Scholar
Andrews, D.W.K. (1984) Nonstrong mixing autoregressive processes. Journal of Applied Probability 21, 930934.CrossRefGoogle Scholar
Barron, A.R. (1993) Universal approximation bounds for superpositions of a sigmoidal function. IEEE Transactions on Information Theory 39, 930944.CrossRefGoogle Scholar
Barron, A.R. (1994) Approximation and estimation bounds for artificial neural networks. Machine Learning 14, 113143.CrossRefGoogle Scholar
Barron, A.R., Cohen, A., Dahmen, W., & DeVore, R.A. (2008) Approximation and learning by greedy algorithms. Annals of Statistics 36, 6494.CrossRefGoogle Scholar
Basrak, B., Davis, R.A., & Mikosch, T. (2002) Regular variation of GARCH processes. Stochastic Processes and Their Applications 99, 95115.CrossRefGoogle Scholar
Bathia, N., Yao, Q., & Ziegelmann, F. (2010) Identifying the finite dimensionality of curve time series. Annals of Statistics 38, 33523386.CrossRefGoogle Scholar
Battey, H. & Sancetta, A. (2013) Conditional estimation for dependent functional data. Journal of Multivariate Analysis 120, 117.CrossRefGoogle Scholar
Bisesti, L., Castagna, A., & Mercurio, F. (2005) Consistent pricing and hedging of an FX options book. Kyoto Economic Review 74, 6583.Google Scholar
Bosq, D. (2000) Linear Processes in Function Spaces: Theory and Applications. Lecture Notes in Statistics, 149. Springer.CrossRefGoogle Scholar
Boucheron, S., Lugosi, G. and Massart, P. (2003) Concentration Inequalities Using the Entropy Method. Annals of Probability 31, 15831614.CrossRefGoogle Scholar
Bradley, R.C. (2005) Basic properties of strong mixing conditions. A survey and some open questions. Probability Surveys 2, 107144.CrossRefGoogle Scholar
Brigo, D. & Mercurio, F. (2006) Interest Rate Models – Theory and Practice. Springer.Google Scholar
Bugni, F.A. (2012) Specification test for missing functional data. Econometric Theory 28, 9591002.CrossRefGoogle Scholar
Bugni, F.A., Hall, P., & Horowitz, J.L. (2009) Goodness-of-fit tests for functional data. The Econometrics Journal 12(Tenth Anniversary Issue), S1S18.CrossRefGoogle Scholar
Bühlmann, P. (2006) Boosting for high-dimensional linear models. Annals of Statistics 34, 559583.CrossRefGoogle Scholar
Bunea, F., Tsybakov, A. and Wegkamp, M. (2007) Aggregation for Gaussian Regression. Annals of Statistics 35, 1674–1697.CrossRefGoogle Scholar
Cai, T. and Yuan, M. (2010) Nonparametric Covariance Function Estimation for Functional and Longitudinal Data. Technical Report.Google Scholar
Castagna, A. & Mercurio, F. (2007) The Vanna–Volga method for implied volatilities. Risk Magazine, 106111.Google Scholar
Dauxois, J., Pousse, A., & Romain, Y. (1982) Asymptotic theory for the principal component analysis of a vector random function: Some applications to statistical inference. Journal of Multivariate Analysis 12, 136154.CrossRefGoogle Scholar
Dehay, D. & Hurd, H.L. (1993) Representation and estimation for periodically and almost periodically correlated random processes. In Gardner, W.A. (ed.), Cyclostationarity in Communications and Signal Processing. IEEE Press.Google Scholar
DeVore, R. & Temlyakov, V. (1996) Some remarks on greedy algorithms. Advances in Computational Mathematics 5, 173187.CrossRefGoogle Scholar
Diebold, F.X. & Li, C. (2006) Forecasting the term structure of government bond yields. Journal of Econometrics 130, 337364.CrossRefGoogle Scholar
Doukhan, P., Massart, P., & Rio, E. (1994) The functional central limit theorem for weakly dependent processes. Annales de l’institut Henri Poincarè, Probabilitès et Statistiques 30, 6382.Google Scholar
Duffie, D. & Kan, R. (1996) A yield-factor model of interest rates. Mathematical Finance 6, 379406.CrossRefGoogle Scholar
Dunford, N. & Schwartz, J.T. (1964) Linear Operators, vol. 1. Interscience Publishers.Google Scholar
Fan, J. (2005) A Selective Overview of Nonparametric Methods in Financial Econometrics (with discussion). Statistical Science 20, 317357.Google Scholar
Fan, J. & Yao, Q. (1998) Efficient estimation of conditional variance functions in stochastic regression. Biometrika 85, 645660.CrossRefGoogle Scholar
Ferraty, F. & Vieu, P. (2006) Nonparametric Functional Data Analysis. Springer.Google Scholar
Ferraty, F., Vieu, P., & Viguier-Pla, S. (2007) Factor-based comparison of groups of curves. Computational Statistics & Data Analysis 51, 49034910.CrossRefGoogle Scholar
Ferraty, F., Quintela-del-Río, A., & Vieu, P. (2012) Specification test for conditional distribution with functional data. Econometric Theory 28, 363386.CrossRefGoogle Scholar
Ferraty, F. (ed.) (2011) Recent Advances in Functional Data Analysis and Related Topics. Springer.CrossRefGoogle Scholar
Ferraty, F. & Romain, Y. (eds.) (2011) The Oxford Handbook of Functional Data Analysis. Oxford University Press.Google Scholar
Geweke, J. (1996) Monte Carlo simulation and numerical integration. In Amman, H.M., Kendrick, D.A., & Rust, J. (eds.), Handbook of Computational Economics, vol. 1, pp. 731800. Elsevier.Google Scholar
Hall, P., Müller, H.G., & Wang, J.-L. (2006) Properties of principal component methods for functional and longitudinal data analysis. Annals of Statistics 34, 14931517.CrossRefGoogle Scholar
Hasbrouck, J. (2007) Empirical Market Microstructure: The Institutions, Economics, and Econometrics of Securities Trading. Oxford University Press.CrossRefGoogle Scholar
Hörmann, S. & Kokoszka, P. (2000) Weakly dependent functional data. Annals of Statistics 38, 18451884.Google Scholar
Horváth, L. & Kokoszka, P. (2012) Inference for Functional Data with Applications. Springer.CrossRefGoogle Scholar
Hu, Y. (2013) Nonparametric estimation of variance function for functional data under mixing conditions. Communications in Statistics – Theory and Methods 42, 17741786.CrossRefGoogle Scholar
Jones, L.K. (1992) A simple lemma on greedy approximation in Hilbert space and convergence rates for projection pursuit regression and neural network training. Annals of Statistics 20, 608613.CrossRefGoogle Scholar
Kargin, V. & Onatski, A. (2008) Curve forecasting by functional autoregression. Journal of Multivariate Analysis 99, 25082526.CrossRefGoogle Scholar
Li, J.Q. & Barron, A.R. (2000) Mixture density estimation. In Solla, S.A., Leen, T.K., & Müller, K.-R. (eds.), Advances in Neural Information Processing Systems, vol. 12, pp. 279285. MIT Press.Google Scholar
Lii, K.-S. & Rosenblatt, M. (2002) Spectral analysis for harmonizable processes. Annals of Statistics 30, 258297.CrossRefGoogle Scholar
Mokkadem, A. (1988) Mixing properties of ARMA processes. Stochastic Processes and Their Applications 29, 309315.CrossRefGoogle Scholar
Müller, H.G., Rituparna, S., & Stadtmüller, U. (2011) Functional data analysis for volatility. Journal of Econometrics 165, 233245.CrossRefGoogle Scholar
Müller, H.G., Stadtmüller, U., & Yao, F. (2006) Functional variance processes. Journal of American Statistical Association 101, 10071018.CrossRefGoogle Scholar
Panaretos, V.M. & Tavakoli, S. (2013a) Cramèr–Karhunen–Loève representation and harmonic principal component analysis of functional time series. Stochastic Processes and Their Applications 123, 27792807.CrossRefGoogle Scholar
Panaretos, V.M. & Tavakoli, S. (2013b) Fourier analysis of stationary time series in function space. Annals of Statistics 41, 568603.CrossRefGoogle Scholar
Pollard, D. (2002) Maximal inequalities via bracketing with adaptive truncation. Annales de l’institut Henri Poincarè, Probabilitès et Statistiques 38, 10391052.CrossRefGoogle Scholar
Ramsay, J.O. & Ramsey, J.B. (2002) Functional data analysis of the dynamics of the monthly index of nondurable goods production. Journal of Econometrics 107, 327344.CrossRefGoogle Scholar
Ramsay, J.O. & Silverman, B.W. (2005) Functional Data Analysis, 2nd ed. Springer.CrossRefGoogle Scholar
Rio, E. (2000) Thèorie Asymptotique des Processus Alèatoires Faiblement Dèpendants. Springer.Google Scholar
Sancetta, A. (2013a) A recursive algorithm for mixture of densities estimation. IEEE Transactions on Information Theory 59, 68936906.CrossRefGoogle Scholar
Tsybakov, A.B. (2003) Optimal Rates of Aggregation. Proceedings of COLT-2003, Lecture Notes in Artificial Intelligence, 303–313.CrossRefGoogle Scholar
Van der Vaart, A. & Wellner, J.A. (2000) Weak Convergence and Empirical Processes. Springer.Google Scholar
Yao, F., Müller, H.-G., & Wang, J.-L. (2005a) Functional data analysis for sparse longitudinal data. Journal of the American Statistical Association 100, 577590.CrossRefGoogle Scholar
Yao, F., Müller, H.-G., & Wang, J.-L. (2005b) Functional linear regression analysis for longitudinal data. Annals of Statistics 33, 28732903.CrossRefGoogle Scholar