Hostname: page-component-848d4c4894-hfldf Total loading time: 0 Render date: 2024-04-30T21:45:09.443Z Has data issue: false hasContentIssue false

On the Existence and Application of Continuous-Time Threshold Autoregressions of Order Two

Published online by Cambridge University Press:  01 July 2016

P. J. Brockwell*
Affiliation:
Royal Melbourne Institute of Technology
R. J. Williams*
Affiliation:
University of California, San Diego
*
Postal address: Department of Statistics and Operations Research, Royal Melbourne Institute of Technology, GPO Box 2476V, Melbourne, Victoria 3001, Australia.
∗∗ Postal address: Department of Mathematics, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093–0112, USA.

Abstract

A continuous-time threshold autoregressive process of order two (CTAR(2)) is constructed as the first component of the unique (in law) weak solution of a stochastic differential equation. The Cameron–Martin–Girsanov formula and a random time-change are used to overcome the difficulties associated with possible discontinuities and degeneracies in the coefficients of the stochastic differential equation. A sequence of approximating processes that are well-suited to numerical calculations is shown to converge in distribution to a solution of this equation, provided the initial state vector has finite second moments. The approximating sequence is used to fit a CTAR(2) model to percentage relative daily changes in the Australian All Ordinaries Index of share prices by maximization of the ‘Gaussian likelihood'. The advantages of non-linear relative to linear time series models are briefly discussed and illustrated by means of the forecasting performance of the model fitted to the All Ordinaries Index.

Type
General Applied Probability
Copyright
Copyright © Applied Probability Trust 1997 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Footnotes

Research supported in part by NSF Grant DMS 9504596 and GER 9023335.

References

[1] Bakry, D. and Emery, M. (1985) Diffusions hypercontractives. Seminaire de Probabilités XIX (Lecture Notes in Mathematics 1123). Springer, New York.Google Scholar
[2] Brockwell, P. J. (1994) On continuous-time threshold ARMA processes. J. Statist. Planning Inf. 39, 291303.CrossRefGoogle Scholar
[3] Brockwell, P. J. and Davis, R. A. (1991) Time Series: Theory and Methods. 2nd edn. Springer, New York.Google Scholar
[4] Chan, K. S., Petruccelli, J. D., Tong, H. and Woolford, S. W. (1985) A multiple threshold AR(1) model. J. Appl. Prob. 22, 267279.Google Scholar
[5] Chung, K. L., and Williams, R. J. (1990) Introduction to Stochastic Integration. 2nd edn. Birkhäuser, Boston.CrossRefGoogle Scholar
[6] Dai, J. G. and Williams, R. J. (1995) Existence and uniqueness of semimartingale reflecting Brownian motions in convex polyhedrons. Theory Prob. Appl. 40, 353 (in Russian). To appear in the SIAM translation of the journal.Google Scholar
[7] Ethier, S. N. and Kurtz, T. G. (1986) Markov Processes: Characterization and Convergence. Wiley, New York.Google Scholar
[8] Granger, C. W. J. and Andersen, A. P. (1978) Non-linear time series modelling. In Applied Time Series Analysis, ed. Findley, D. F.. Academic Press, New York.Google Scholar
[9] Ikeda, N. and Watanabe, S. (1981) Stochastic Differential Equations and Diffusion Processes. North Holland, Amsterdam.Google Scholar
[10] Jones, R. H. (1981) Fitting a continuous time autoregression to discrete data. In Applied Time Series Analysis II. ed. Findley, D. F.. Academic Press, New York. pp 651682.Google Scholar
[11] Kurtz, T. G. (1990) Martingale problems for constrained Markov problems. In Recent Advances in Stochastic Calculus. Ed. Baras, J. and Mirelli, V.. Springer, New York.Google Scholar
[12] Mcleod, A. I. and Li, W. K. (1983) Diagnostic checking ARMA time series models using squared-residuals autocorrelations. J. Time Series Analysis 4, 269273.Google Scholar
[13] Nicholls, D. F. and Quinn, B. G. (1974) Random Coefficient Autoregressive Models: An Introduction (Lecture Notes in Statistics 11). Springer, New York.Google Scholar
[14] Nisio, M. (1973) On the existence of solutions of stochastic differential equations. Osaka J. Math. 10, 185208.Google Scholar
[15] Petruccelli, J. D. (1990) A comparison of tests for SETAR-type non-linearity in time series. J. Forecasting 9, 2536.CrossRefGoogle Scholar
[16] Stroock, D. W. and Varadhan, S. R. S. (1979) Multidimensional Diffusion Processes. Springer, New York.Google Scholar
[17] Subba Rao, T. and Gabr, M. M. (1984) An Introduction to Bispectral Analysis and Bilinear Time Series Models (Lecture Notes in Statistics 24). Springer, New York.Google Scholar
[18] Tong, H. (1983) Threshold Models in Non-linear Time Series Analysis. (Lecture Notes in Statistics 21). Springer, New York.Google Scholar
[19] Tong, H. (1990) Non-linear Time Series: A Dynamical System Approach. Clarendon Press, Oxford.CrossRefGoogle Scholar
[20] Tsay, R. S. (1989) Testing and modeling threshold autoregressive processes. J. Amer. Statist. Assoc. 84, 231240.CrossRefGoogle Scholar
[21] Varadhan, S. R. S. and Williams, R. J. (1985) Brownian motion in a wedge with oblique reflection. Commun. Pure Appl. Math. 38, 405443.Google Scholar