Detecting seasonal unit roots in a structural time series model

In this paper, we propose to detect seasonal unit roots within the context of a structural time series model. Such a model is often found to be useful in practice. Using Monte Carlo simulations, we show that our method works well. We illustrate our approach for several quarterly macroeconomic time series variables.     

Cultural Hegemony of Singapore among ASEAN Countries: Globalization and Cultural Policy

Abstract: Singapore had been called a Cultural Desert since its independence in 1965, but from the beginning of 1990s, there has been a significant change. The Singapore Government started to call their city a “Global City for the Arts”, making numerous cultural policy changes. They also worked on various cultural experiments to establish their cultural leadership or hegemony among Association of South East Asian Nations (ASEAN) countries. The development of arts policies, cultural industries and people's positive commitment towards cultural exchanges are examples of this change. Singapore therefore is now playing the role of the cultural hub among the ASEAN countries. As an example of this, the present study discusses “Esplanade”, which opened as a huge cultural complex in October 2002. Then the paper will also discuss both bright and dark sides of the cultural development in Singapore. As a conclusion, this paper discusses the possibility of the cultural contribution of Singapore to ASEAN countries, in spite of having serious epistemological discontinuity among ASEAN.     

Lifestyles and identity maintenance among gay Japanese-American males

An exploratory study of thirteen Japanese-American gay men residing in the Los Angeles area found that those men who had disclosed their sexual orientation to family members were more likely to express more positive attitudes concerning a variety of issues. Detailed personal accounts of these patterns are presented along with discussions of how Asian homosexuals maintain their “double-minority” identities as both Japanese and gay.     

Bayesian sample‐size determination methods considering both worthwhileness and unpromisingness for exploratory two‐arm randomized clinical trials with binary endpoints

A randomized exploratory clinical trial comparing an experimental treatment with a control treatment on a binary endpoint is often conducted to make a go or no‐go decision. Such an exploratory trial needs to have an adequate sample size such that it will provide convincing evidence that the experimental treatment is either worthwhile or unpromising relative to the control treatment. In this paper, we propose three new sample‐size determination methods for an exploratory trial, which utilize the posterior probabilities calculated from predefined efficacy and inefficacy criteria leading to a declaration of the worthwhileness or unpromisingness of the experimental treatment. Simulation studies, including numerical investigation, showed that all three methods could declare the experimental treatment as worthwhile or unpromising with a high probability when the true response probability of the experimental treatment group is higher or lower, respectively, than that of the control treatment group.     

Child care arrangements and fertility: An analysis of two-earner households

The determinants of child care arrangements and relations between child care and fertility are examined using data on two-earner households from the 1976 National Survey of Family Growth. We find that the probability of relying on market arrangements is higher among families in which the husband's income, the wife's wage, and the level of the wife's labor supply are high; these households are likely to benefit the most from subsidies to the market forms of care that are small relative to the total cost of care (e.g. the present system of tax credits). In addition, parental education, family size, child's age, race, religion, and place of residence have important influences on the choice of child care mode. When other factors are held constant, reliance on a relative for child care is positively associated with intentions to have further children among couples with infants and preschoolers.     

A Two Sample Test for Mean Vectors with Unequal Covariance Matrices

In this paper, we consider testing the equality of two mean vectors with unequal covariance matrices. In the case of equal covariance matrices, we can use Hotelling’s T² statistic, which follows the F distribution under the null hypothesis. Meanwhile, in the case of unequal covariance matrices, the T² type test statistic does not follow the F distribution, and it is also difficult to derive the exact distribution. In this paper, we propose an approximate solution to the problem by adjusting the degrees of freedom of the F distribution. Asymptotic expansions up to the term of order N^{? 2} for the first and second moments of the U statistic are given, where N is the total sample size minus two. A new approximate degrees of freedom and its bias correction are obtained. Finally, numerical comparison is presented by a Monte Carlo simulation.     

A Bayesian inference of P(λ1<λ2) for two Poisson parameters

The statistical inference drawn from the difference between two independent Poisson parameters is often discussed in the medical literature. However, such discussions are usually based on the frequentist viewpoint rather than the Bayesian viewpoint. Here, we propose an index θ=P(λ_{1, post}<λ_{2, post}), where λ_{1, post} and λ_{2, post} denote Poisson parameters following posterior density. We provide an exact and an approximate expression for calculating θ using the conjugate gamma prior and compare the probabilities obtained using the approximate and the exact expressions. Moreover, we also show a relation between θ and the p-value. We also highlight the significance of θ by applying it to the result of actual clinical trials. Our findings suggest that θ may provide useful information in a clinical trial.     

A Bayesian non‐inferiority test for two independent binomial proportions

In drug development, non‐inferiority tests are often employed to determine the difference between two independent binomial proportions. Many test statistics for non‐inferiority are based on the frequentist framework. However, research on non‐inferiority in the Bayesian framework is limited. In this paper, we suggest a new Bayesian index τ = P(π₁ > π₂ ? Δ₀ | X₁,X₂), where X₁ and X₂ denote binomial random variables for trials n₁ and n₂, and parameters π₁ and π₂, respectively, and the non‐inferiority margin is Δ₀ > 0. We show two calculation methods for τ, an approximate method that uses normal approximation and an exact method that uses an exact posterior PDF. We compare the approximate probability with the exact probability for τ. Finally, we present the results of actual clinical trials to show the utility of index τ. Copyright © 2013 John Wiley & Sons, Ltd.     

Least squares parameter estimation in multiplicative noise models

A simple multiplicative noise model with a constant signal has become a basic mathematical model in processing synthetic aperture radar images. The purpose of this paper is to examine a general multiplicative noise model with linear signals represented by a number of unknown parameters. The ordinary least squares (LS) and weighted LS methods are used to estimate the model parameters. The biases of the weighted LS estimates of the parameters are derived. The biases are then corrected to obtain a second-order unbiased estimator, which is shown to be exactly equivalent to the maximum log quasi-likelihood estimation, though the quasi-likelihood function is founded on a completely different theoretical consideration and is known, at the present time, to be a uniquely acceptable theory for multiplicative noise models. Synthetic simulations are carried out to confirm theoretical results and to illustrate problems in processing data contaminated by multiplicative noises. The sensitivity of the LS and weighted LS methods to extremely noisy data is analysed through the simulated examples.