Signal Extraction Problems in Seismology*

The earth's surface is under continuous influence of a variety of natural forces such as the effect of past earthquakes, wave, wind, tide, air pressure, precipitation and a variety of human induced sources. Since it is almost impossible to describe the response to these noise inputs precisely, for automatic processing of seismic data, proper statistical modeling is necessary. In this paper, we describe four specific examples of time series modeling for signal extraction problems related to seismology. Namely, we consider 1) the estimation of the arrival time of a seismic signal, 2) the extraction of small seismic signal from noisy data, 3) the detection of the coseismic effect in groundwater level data contaminated by various effects from air pressure etc., and 4) the estimation of changing spectral characteristic of seismic record.     

Delay dynamics in nonlinear monopoly with gradient adjustment

Decisions in Economics and Finance - Two types of boundedly rational monopolists are considered, when they are unable to determine the profit maximizing output levels. In the first case, the...     

Dynamic programming and mean-variance hedging with partial execution risk

In this paper I consider a hedging problem in an illiquid market where there is a risk that the hedger’s order to buy or sell the underlying asset may be executed only partially. In this setting, I find a mean-variance optimal hedging strategy by the dynamic programming method. The solution contains a new endogenous state variable representing the current position in the underlying. The exogenous coefficients in the solution are given by recursive formulas which can be calculated efficiently in Markov models. I illustrate effects of the partial execution risk in several examples.      

News shocks and asset price volatility in general equilibrium

We study equity price volatility in general equilibrium with news shocks about future productivity and monetary policy. As West (1988) shows, in a partial equilibrium present discounted value model, news about the future cash flow reduces asset price volatility. We show that introducing news shocks in a canonical dynamic stochastic general equilibrium model may not reduce asset price volatility under plausible parameter assumptions. This is because, in general equilibrium, the asset cash flow itself may be affected by the introduction of news shocks. In addition, we show that neglecting to account for policy news shocks (e.g., policy announcements) can potentially bias empirical estimates of the impact of monetary policy shocks on asset prices.     

Consumer valuation of energy-saving features of residential air conditioners with hedonic and choice models

The promotion of energy-efficient appliances is necessary to reduce the energetic and environmental burden of the household sector. However, many studies have reported that a typical consumer underestimates the benefits of energy-saving investment on the purchase of household electric appliances. To analyze this energy-efficiency-gap problem, many scholars have estimated implicit discount rates that consumers use for energy-consuming durables. Although both hedonic and choice models have been used in previous studies, a comparison between the two models has not yet been made. This study uses point-of-sale data about Japanese residential air conditioners and estimates implicit discount rates with both hedonic and choice models. Both models demonstrate that a typical consumer underinvests in energy efficiency. Although choice models generally estimate a lower implicit discount rate than hedonic models, the latter models estimate the values of other product characteristics more consistently than choice models.     

Development of a model to estimate the economic impacts of R&D output of public research institutes

This paper proposes a modeling framework to estimate the economic impacts of R&D output of public research institutes. The framework models the process of R&D output generating the economic impacts. The authors collect case data of market‐creation economic impacts originating from R&D output of the National Institute of Advanced Industrial Science and Technology, Japan. On the basis of the case studies, the process of R&D output generating economic impacts is modeled in the following four stages: (1) R&D output, (2) technology transfer, (3) commercialization, and (4) market impacts. The model describes these stages using six parameters. This paper presents the model and case studies, and discusses the application of the model.     

The Price of Being Foreign: Stock Market Penalties Associated with Accounting Irregularities for U.S.-Listed Foreign Firms

We examine the stock market consequences of disclosing accounting irregularities for U.S.-listed foreign firms. After controlling for the severity of the irregularity and other firm characteristics, we find that foreign firms experience significantly more negative short-window stock market reactions following irregularity announcements than do U.S. firms. Moreover, for a subsample of 64 irregularities of foreign firms that are listed on both a U.S. and home country stock exchange, we find evidence that restating firms' U.S. investors react more negatively to the same irregularity than their home country investors. This differential market reaction appears related to firm-specific information risks that are greater for foreign firms than U.S. firms. Collectively, consistent with the reputational bonding hypothesis in prior literature, our results suggest that accounting irregularities cause U.S. investors to reassess the information risk associated with foreign firms.     

Delay Dynamics in a Classical IS‐LM Model with Tax Collections

An IS‐LM model is developed for the dynamics of income, interest rate and money stock with delay in tax revenue. The main aim is to show that the delay matters in macro dynamics. Two different delays, fixed time delays and continuously distributed time delays, are considered explicitly and described by delay‐differential equations and integro‐differential equations, respectively. Conditions for the local stability of the two models are derived and compared. The destabilizing effects caused by the delay are numerically examined. Appearance of wide spectrum of dynamics ranging from simple cyclic oscillations to complex dynamics is described through Hopf bifurctions.