Double unit root tests for cross-sectionally dependent panel data

This paper proposes various double unit root tests for cross-sectionally dependent panel data. The cross-sectional correlation is handled by the projection method [P.C.B. Phillips and D. Sul, Dynamic panel estimation and homogeneity testing under cross section dependence, Econom. J. 6 (2003), pp. 217–259; H.R. Moon and B. Perron, Testing for a unit root in panels with dynamic factors, J. Econom. 122 (2004), pp. 81–126] or the subtraction method [J. Bai and S. Ng, A PANIC attack on unit roots and cointegration, Econometrica 72 (2004), pp. 1127–1177]. Pooling or averaging is applied to combine results from different panel units. Also, to estimate autoregressive parameters the ordinary least squares estimation [D.P. Hasza and W.A. Fuller, Estimation for autoregressive processes with unit roots, Ann. Stat. 7 (1979), pp. 1106–1120] or the symmetric estimation [D.L. Sen and D.A. Dickey, Symmetric test for second differencing in univariate time series, J. Bus. Econ. Stat. 5 (1987), pp. 463–473] are used, and to adjust mean functions the ordinary mean adjustment or the recursive mean adjustment are used. Combinations of different methods in defactoring to eliminate the cross-sectional dependency, integrating results from panel units, estimating the parameters, and adjusting mean functions yields various available tests for double unit roots in panel data. Simple asymptotic distributions of the proposed test statistics are derived, which can be used to find critical values of the test statistics.

We perform a Monte Carlo experiment to compare the performance of these tests and to suggest optimal tests for a given panel data. Application of the proposed tests to a real data, the yearly export panel data sets of several Latin–American countries for the past 50 years, illustrates the usefulness of the proposed tests for panel data, in that they reveal stronger evidence of double unit roots than the componentwise double unit root tests of Hasza and Fuller [Estimation for autoregressive processes with unit roots, Ann. Stat. 7 (1979), pp. 1106–1120] or Sen and Dickey [Symmetric test for second differencing in univariate time series, J. Bus. Econ. Stat. 5 (1987), pp. 463–473].     

Bayesian analysis of paired survival data using a bivariate exponential distribution

We consider a Bayesian analysis method of paired survival data using a bivariate exponential model proposed by Moran (1967, Biometrika 54:385–394). Important features of Moran’s model include that the marginal distributions are exponential and the range of the correlation coefficient is between 0 and 1. These contrast with the popular exponential model with gamma frailty. Despite these nice properties, statistical analysis with Moran’s model has been hampered by lack of a closed form likelihood function. In this paper, we introduce a latent variable to circumvent the difficulty in the Bayesian computation. We also consider a model checking procedure using the predictive Bayesian P-value.     

What drives successful social networking services? A comparative analysis of user acceptance of Facebook and Twitter

This study identifies perceived mobility, security, connectedness, system and service quality, usefulness, attitude, and flow experience as key motivational factors for using social networking services (SNSs), and develops a theoretical model that explicates the process in which users adopt Facebook and Twitter by integrating these factors with the technology acceptance model (TAM). While results of structural equation modeling (SEM) on the collected data (N = 2,214) verified the validity and reliability of the research model, Facebook and Twitter users were found to emphasize different motivational factors when deciding to use SNSs. The implications of notable findings and directions for future studies are discussed.     

Insights on medical tourism: markets as networks and the role of strong ties

Despite a huge amount of speculation and expectation surrounding medical tourism, hard empirical evidence is only now beginning to emerge. This paper widens the focus of discussion by contrasting two country experiences (UK and Korea) which on the surface illustrate the diversity of medical tourism and little else. However, considered more comparatively, the accounts contribute toward wider, albeit tentative, theoretical understandings, and insights. The paper is drawn from two broad programs of empirical study conducted over three years in UK and Korea, respectively. The article is structured in three parts: first, a brief overview of policy, legislative, and accreditation frameworks that exist to govern medical tourist flows. Second, we present evidence around flows, demographics, treatment, and medical tourism for Korea and UK (both for supply and demand). Third, we examine conceptual and theoretical implications of this evidence. We argue that viewing medical tourism as a global market is problematic; some medical tourist markets are best viewed as networks with long-term exchange relationships; some specific areas of activity do function more strongly as price-related; decision making around medical tourism frequently involves a range of information and social networks (economic action as embedded social structure); and medical tourism is a function of globalization.     

Changes in attitude towards people with mental illness in P-city,S. Korea: a comparison between the years 2000 and 2010

The objective of this study was to investigate changes in the attitudes towards people with mental illness in a city located in South Korea (P-city) between 2010 and 2000. Since it was not accessible to raw data of 2000, to compare with 2000 results, the results from the previous research article were used. Results from t-tests and ANCOVA analyses showed positive changes in P-city residents’ attitudes towards people with mental illness, particularly in authoritarianism and social restrictiveness. Discussion includes the role of a successful community mental health centre in bringing about such positive attitudinal changes.     

Inter-organizational information systems visibility in buyer–supplier relationships: The case of telecommunication equipment component manufacturing industry

The concept and operation of supply chain (SC) visibility remain underexplored questions in supply chain management, as is the question of the facilitating role of inter-organizational information systems (IOIS) in achieving SC visibility. This paper seeks to elaborate on the novel concept of IOIS visibility and to explore the antecedents and consequences of IOIS visibility. Investigating SC cooperation from the perspectives of both partners (buyers and suppliers) is important, especially when channel partners depend on each other and when asymmetries in IOIS visibility can exist.     

红外吸收峰的位置波动:归因于单一谱带的频移还是重叠谱带相对强度的变化?

红外吸收峰的位置波动可能由单一谱带的实际频移或是邻近重叠谱带相对强度的变化而产生。本文通过主成分分析法(PCA)有力地证明了光谱位置波动的根源往往归因于后一种机理。PCA能灵敏有效地区分单一谱带的实际频移与由重叠谱带相对强度变化所产生的最大峰移。对于由分子相互作用强度变化所诱导,并在振动光谱领域较为常见的所谓带移的概念,往往由于其隐含了谱带的固有频移而有些概念误导。在许多红外光谱中,峰极大值表面的位移,一般产生于两条重叠谱带相对贡献的变化,而不是分子相互作用强度变化所诱导的单一谱带的缓慢频移。这个观点可以帮助我们解释振动光谱所探测到的分子相互作用。     

Propaganda or public relations campaign? International communication on the war against Iraq

Cross-cultural survey on the war against Iraq from different cultures may help to assess whether the public relations war has succeeded or failed. Overall the public of the U.S. and the U.K. formed similar evaluations of the war; whereas South Korean opinion was lay on the opposite side of the continuum. The present study suggests that public relations campaigns administered by the U.S. government did not generate favorable opinions in countries other than the U.S.     

Status of organization–public relationship research from an analysis of published articles, 1985–2004

This study analyzes trends and patterns of research about organization-public relationships (OPR) through a content analysis of articles published between 1985 and 2004. The current status of OPR studies suggests that we have made progress in OPR research over the past two decades but need to explicate, replicate and extend the existing studies and cumulate the research trend.