In this paper, we consider the matrix vectorization operator termed the vecd operator, which has recently been introduced in the literature. This operator stacks up distinct elements of a symmetric matrix in a way that differs from that of the well-known vech operator; it stacks up not columns,...

A recursive formula for computing the exact value of score vectors is proposed, which is more desirable than approximate values in some statistical analyses, for a general form of the linear Gaussian state space model. Unlike most extant methods, our formula calculates all components of the...

Recently Chiba and Kobayashi (2013) have proposed the Lagrange multiplier (LM) test for the null hypothesis that volatilities of two asset return processes are driven by only one stochastic volatility (SV) process in a bivariate SV model. They apply their LM test to Asian stock market index...

In this paper, we propose a test for coefficient stability of an AR(1) model against the random coefficient autoregressive model of order 1 neither assuming a stationary nor a non-stationary process under the null hypothesis of a constant coefficient. The proposed test is obtained as a...

In this article, we develop the asymptotic theory of Hwang and Basawa (2005) for explosive random coefficient autoregressive (ERCA) models. Applying the theory, we prove that a locally best invariant (LBI) test in McCabe and Tremayne (1995), which is for the null of a unit root (UR) process...

In this note, I review how to impose the stationarity and invertibility conditions in estimating ARMA models with unconstrained optimization. Specifically, I reintroduce a convenient transformation of unconstrained variables proposed by Jones (1980), illustrating how to compute its inverse...

In this note, I consider a general class of unobserved components (UC) models and derive a relevant inequality. This inequality implies that either of the two assumptions of standard UC models, namely, a random walk trend and uncorrelated shocks, is not satisfied if the impulse response measure...

We call the realized variance (RV), calculated with observed prices contaminated by (market) microstructure noises (MNs), the noise-contaminated RV (NCRV), and refer to the bias component in the NCRV, associated with the MNs, as the MN component. This paper develops a state space method for...