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In this study, we consider a four-regime bubble model under the assumption of time-varying volatility and propose the algorithm of estimating the break dates with volatility correction: First, we estimate the emerging date of the explosive bubble, its collapsing date, and the recovering date to the normal market under assumption of homoskedasticity; second, we collect the residuals and then employ the WLS-based estimation of the bubble dates. We demonstrate by Monte Carlo simulations that the accuracy of the break dates estimators improve significantly by this two-step procedure in some cases compared to those based on the OLS method.

In this study, we extend the three-regime bubble model of Pang et al. (2021) to allow the forth regime followed by the unit root process after recovery. We provide the asymptotic and finite sample justification of the consistency of the collapse date estimator in the two-regime AR(1) model. The consistency allows us to split the sample before and after the date of collapse and to consider the estimation of the date of exuberation and date of recovery separately. We have also found that the limiting behavior of the recovery date varies depending on the extent of explosiveness and recovering.

This paper is devoted to testing for the explosive bubble under time-varying non-stationary volatility. Because the limiting distribution of the seminal Phillips et al. (2011) test depends on the variance function and usually requires a bootstrap implementation under heteroskedasticity, we construct the test based on a deformation of the time domain. The proposed test is asymptotically pivotal under the null hypothesis and its limiting distribution coincides with that of the standard test under homoskedasticity, so that the test does not require computationally extensive methods for inference. Appealing finite sample properties are demonstrated through Monte-Carlo simulations. An empirical application demonstrates that the upsurge behavior of cryptocurrency time series in the middle of the sample is partially explained by the volatility change.

This paper presents a new method for a quick similarity-based search through long unlabeled audio streams to detect and locate audio clips provided by users. The method involves feature-dimension reduction based on a piecewise linear representation of a sequential feature trajectory extracted from a long audio stream. Two techniques enable us to obtain a piecewise linear representation: the dynamic segmentation of feature trajectories and the segment-based Karhunen-L\'{o}eve (KL) transform. The proposed search method guarantees the same search results as the search method without the proposed feature-dimension reduction method in principle. Experiment results indicate significant improvements in search speed. For example the proposed method reduced the total search time to approximately 1/12 that of previous methods and detected queries in approximately 0.3 seconds from a 200-hour audio database., Comment: 20 pages, to appear in IEEE Transactions on Audio, Speech and Language Processing

Several Phillips curves based on sticky information and sticky prices are estimated and compared using Bayesian VAR-GMM. This method derives expectations in each Phillips curve from a VAR and estimates the Phillips curve parameters and the VAR coefficients simultaneously. Quasi-marginal likelihood-based model comparison selects a dual stickiness Phillips curve in which, each period, some prices remain unchanged, consistent with micro evidence. Moreover, sticky information is a more plausible source of inflation inertia in the Phillips curve than other sources proposed in previous studies. Sticky information, sticky prices, and unchanged prices in each period are all needed to better describe inflation dynamics. [ABSTRACT FROM AUTHOR]

Should monetary policy offset the effects of labor supply shocks on inflation and the output gap? Canonical New Keynesian models answer yes. Motivated by weak labor force participation during the pandemic, we reexamine the question by introducing labor force entry and exit in an otherwise canonical model with sticky prices and wages. The entry decision generates an employment channel of monetary policy, by which a decline in employment raises wage growth. Consequently, a labor supply shock to the value of nonparticipation in the labor market induces a policy trade-off between stabilization of the employment gap and wage growth. For an adverse labor supply shock, optimal policy dampens the decline in employment to rein in wage growth, which entails a period of higher inflation and a positive output gap. A welfare analysis of policy rules shows that monetary policy should not lean against the employment gap. [ABSTRACT FROM AUTHOR]

Empirical studies have documented that the persistence of the gap between inflation and its trend declined after the Volcker disinflation. Previous research into the source of the decline has offered competing views while sidestepping the possibility of equilibrium indeterminacy. This paper examines the source by estimating a medium-scale DSGE model using a Bayesian method that allows for indeterminacy. The estimated model shows that the Fed's change from a passive to an active policy response to the inflation gap or a decrease in firms' probability of price change can fully account for the decline in inflation gap persistence by ruling out indeterminacy that induces persistent dynamics of the economy. [ABSTRACT FROM AUTHOR]

Recent studies indicate that, since 1980, the average markup and the profit share of income have increased, while the labor share and the investment share of spending have decreased. We examine the role of monetary policy in these changes as inflation has concurrently trended down. In a simple staggered price model with a non-CES aggregator of differentiated goods, a decline in trend inflation as measured since 1980 can account for a substantial portion of the changes. Moreover, introducing a rise in the productivity of "superstar firms" in the model can better explain not only the macroeconomic changes but also the micro evidence on the distribution of firms' markups, including the flat median markup. [ABSTRACT FROM AUTHOR]

In staggered price models, a non-CES aggregator of differentiated goods generates empirically plausible short- and long-run trade-offs between output and inflation: lower trend inflation flattens the Phillips curve and decreases steady-state output by increasing markups. We show that the aggregator reduces both the steady-state welfare cost of higher trend inflation and the inflationrelated weight in a model-based welfare function for higher trend inflation. Consequently, optimal trend inflation is moderately positive even without considering the zero lower bound on nominal interest rates. Moreover, the welfare difference between 2 percent and 4 percent inflation targets is much smaller than in the CES aggregator case. [ABSTRACT FROM AUTHOR]

We propose a novel theory of intrinsic inflation persistence by introducing trend inflation and variable elasticity of demand in a model with staggered price and wage setting. Under nonzero trend inflation, the variable elasticity generates intrinsic persistence in inflation through a measure of price dispersion stemming from staggered price setting. It also introduces intrinsic persistence in wage inflation under staggered wage setting, which affects price inflation. With the theory we show that inflation exhibits a persistent, hump-shaped response to a monetary policy shock. We also show that a credible disinflation leads to a gradual decline in inflation and a fall in output, and lower trend inflation reduces inflation persistence, as observed around the time of the Volcker disinflation. [ABSTRACT FROM AUTHOR]

A large literature with canonical New Keynesian models has established that the Fed's policy change from a passive to an active response to inflation led to U.S. macro- economic stability after the Great Inflation of the 1970s. We revisit this view by estimating a staggered price model with trend inflation using a Bayesian method that allows for equilibrium indeterminacy and adopts a sequential Monte Carlo algorithm. The model empirically outperforms a canonical New Keynesian model and demon- strates an active response to inflation even in the Great Inflation era, during which the U.S. economy was likely in the indeterminacy region of the model's parameter space. A more active response to inflation alone does not suffice for explaining the shift to determinacy after the Great Inflation, unless it is accompanied by a decline in trend inflation or a change in policy responses to the output gap and output growth. [ABSTRACT FROM AUTHOR]

Persistent responses of ination to monetary policy shocks have been difficult to explain by existing models of the monetary transmission mechanism without embedding controversial intrinsic inertia of ination. Our paper addresses this issue using a staggered price model with trend ination, a smoothed-off kink in demand curves, and a fixed cost of production. In this model, ination exhibits a persistent response to a policy shock even in the absence of its intrinsic inertia, because the kink causes a measure of price dispersion, which is intrinsically inertial, to become a key source of inflation persistence under the positive trend inflation rate. In addition, output and labor productivity both rise after an expansionary policy shock as in an estimated structural vector autoregression model. Moreover, credible disinflation induces a gradual decline in inflation and a fall in output as observed during the Volcker disination era. [ABSTRACT FROM AUTHOR]

What caused the U.S. economy's shift from the Great Inflation era to the Great Moderation era? A large literature shows that the shift was achieved by the change in monetary policy from a passive to an active response to inflation. However, Coibion and Gorodnichenko (2011) attribute the shift to a fall in trend inflation along with the policy change, based on a solely estimated Taylor rule and a calibrated staggered-price model. We estimate the Taylor rule and the staggered-price model jointly and demonstrate that the change in monetary policy responses to inflation and other variables suffices for explaining the shift. [ABSTRACT FROM AUTHOR]

A pitfall of expectational stability (E-stability) analysis can arise in models with multi-period expectations: if an auxiliary variable is introduced as substitute for an expectational endogenous variable in such a model, this shrinks the region of the model parameters that guarantee E-stability of a fundamental rational expectations equilibrium. Moreover, in the model representation with no auxiliary variable, the same E-stability region as in that with the auxiliary variable is obtained if economic agents are assumed to make multiple forecasts in an inconsistent manner. Therefore, we argue that the introduction of an auxiliary variable as substitute for an expectational endogenous variable in models with multi-period expectations can induce misleading implications that are biased toward E-instability. [ABSTRACT FROM AUTHOR]

In a Calvo sticky price model based on micro evidence that each period a fraction of prices is kept unchanged, we examine implications of firm-specific labor for determinacy and expectational stability (E-stability) of rational expectations equilibrium under interest rate policy. Firm-specific labor causes higher trend inflation to be more likely to induce not only indeterminacy but also E-instability. The latter is in contrast with the result of E-stability in the case of homogeneous labor analyzed in recent research. Moreover, under the same calibration of structural model parameters, indeterminacy and E-instability are much more likely in the case of firm-specific labor than in the case of homogeneous labor. The recent argument--a decline in trend inflation along with the Fed's change from a passive to an active policy response to inflation explains much of the U.S. economy's shift from indeterminacy during the Great Inflation era to determinacy during the Great Moderation era--depends crucially on the assumption of firm-specific labor. [ABSTRACT FROM AUTHOR]