Issues in the estimation and application of latent structure models of choice

Our paper provides a brief review and summary of issues and advances in the use of latent structure and other finite mixture models in the analysis of choice data. Focus is directed to three primary areas: (1) estimation and computational issues, (2) specification and interpretation issues, and (3) future research issues. We comment on what latent structure models have promised, what has been, to date, delivered, and what we should look forward to in the future.     

Vulnerability and industrial hazards in industrializing countries: an integrative approach

The extra vulnerability of industrializing countries to environmental problems and industrial accidents cannot be understood or solved by a ‘normal’ scientific analysis. Aspects of the social and institutional context must be included, through analyses based on post-normal science. The standard two-dimensional classification of PNS is modified to have axes ‘social ‘and institutional vulnerabilities’ and ‘complexity of technological hazards’. The analysis is mainly applied to the case of the relatively rare accidents with catastrophic potential. In these, the deaths per accident in India, Mexico and Brazil are much greater than in the industrialized countries. This discrepancy arises partly from location of such plants near residential communities for marginalized workers and their families. Other socio-political factors are relevant, as the role of these countries in the global production system, the enforcement of safety and planning laws, quality of housing, and lifestyle of residents. Reducing the vulnerability of industrializing countries will therefore require major social policies and a comprehension of the limits of the normal scientific and economic approaches to such problems.     

THE DISTRIBUTION OF HOUSEHOLD INCOME AND EXPENDITURE IN PORTUGAL: 1980 AND 1990

From 1980 to 1990 Portugal experienced a generalized liberalization of economic activity, due in large part to its 1986 integration in the European Union. This paper studies the changes in the Portuguese distribution of household income and expenditure during this period, using micro-data on household budgets and applying recent developments in statistical inference for Lorenz curves. We find a significant increase in six measures of welfare and an unambiguous decrease in the inequality of the respective distributions. Different explanations for the findings of decreased inequality are discussed.     

UNEMPLOYMENT, HYSTERESIS AND TRANSITION

In this paper, we quantify the degree of persistence in the unemployment rates of transition countries using a variety of methods benchmarked against the EU. Initially, we work with the concept of linear ‘Hysteresis’ as described by the presence of unit roots in unemployment as in most empirical research on this area. Given that this is potentially a narrow definition, we also take into account the existence of structural breaks and nonlinear dynamics in unemployment. Finally, we examine whether CEECs' unemployment presents features of multiple equilibria, that is, if it remains locked into a new level whenever some structural change or sufficiently large shock occurs. Our findings show that, in general, we can reject the unit‐root hypothesis after controlling for structural changes and business‐cycle effects, but we can observe the presence of a high and low unemployment equilibria. The speed of adjustment is faster for CEECs than the EU, although CEECs tend to move more frequently between equilibria.     

How similar is the world in the internet era? A comparison of e‐business in China,Russia, and Sweden

Much has been written about how e‐business can serve as a strong homogenizing influence and essentially make the world into one market. Yet, little research has empirically investigated this question. This study seeks to describe e‐business activity in China, Sweden, and Russia to identify similarities and differences in the portfolios of e‐business applications in these countries. Our results indicate that different e‐business applications are emerging as more prevalent in different countries. © 2006 Wiley Periodicals, Inc.     

Awareness of Distributed Denial of Service Attacks' Dangers: Role of Internet Pricing Mechanisms

Denial of Service (DoS) attacks consist of overwhelming a server, a network or a Web site in order to paralyze its normal activity. The additional parameter in Distributed Denial of Service (DdoS) attacks is the distributing strategy. It means that DDoS attacks do not come from a single computer but stem from all accessible channels and servers. Consequences are multiple, ranging from system errors, temporary inability to access the Web site for normal users to challenging the actual reliability of the Internet. Despite this, Internet users show carelessness. The explanation lies in the specificities of DDoS attacks. We explore possibilities to raise users' awareness about the actual amplitude of problems caused by DDoS attacks. We suggest a careful examination of Internet pricing mechanisms and switching from flat to usage-constraining pricing schemes.     

The Essential Features of Technology and Technology Education: A Conceptual Framework for the Development of OBE (Outcomes Based Education) Related Programmes in Technology Education

It appears that programme development in technology education is emerging from an atheoretical perspective. This could be attributed to the absence/neglect of conceptual frameworks (philosophical underpinning) in the development of programmes in technology education. This article explores the role of the content dimension of the 'essential features' of technology and technology education in OBE (Outcomes Based Education) related programme development. An instructional programme was developed using criteria derived from the essential features of technology and technology education. In order to gauge learners' experience, in relation to these essential features, a qualitative case study involving 20 learners was undertaken at a College of Education. Engagement with theprogramme proved to be an empowering experience for the learners who had hitherto not had the opportunity to experience a formal programme in technology education. Although it could not be proved conclusively that cognitive development had occurred, positive inter-dependence,shared responsibility, social skills and enhanced learning were evident. The study has shown that criteria derived from the 'essential features' of technology and technology education could serve as a reliable yardstick to measure the extent of learning in relation to these essential features     

A comparison of several approximations to the power function of the likelihood ratio test in covariance structure analysis*

In this paper we compare alternative asymptotic approximations to the power of the likelihood ratio test used in covariance structure analysis for testing the fit of a model. Alternative expressions for the noncentrality parameter (ncp) lead to different approximations to the power function. It appears that for alternative covariance matrices close to the null hypothesis, the alternative ncp's lead to similar values, while for alternative covariance matrices far from H_o the different expressions for the ncp can conflict substantively. Monte Carlo evidence shows that the ncp proposed in Satorra and Saris (1985) gives the most accurate power approximations.