The Impact of Joint Responses of Devices in an Airport Security System

In this article, we consider a model for an airport security system in which the declaration of a threat is based on the joint responses of inspection devices. This is in contrast to the typical system in which each check station independently declares a passenger as having a threat or not having a threat. In our framework the declaration of threat/no-threat is based upon the passenger scores at the check stations he/she goes through. To do this we use concepts from classification theory in the field of multivariate statistics analysis and focus on the main objective of minimizing the expected cost of misclassification. The corresponding correct classification and misclassification probabilities can be obtained by using a simulation-based method. After computing the overall false alarm and false clear probabilities, we compare our joint response system with two other independently operated systems. A model that groups passengers in a manner that minimizes the false alarm probability while maintaining the false clear probability within specifications set by a security authority is considered. We also analyze the staffing needs at each check station for such an inspection scheme. An illustrative example is provided along with sensitivity analysis on key model parameters. A discussion is provided on some implementation issues, on the various assumptions made in the analysis, and on potential drawbacks of the approach.     

Pressures towards and against formalization: Regulation and informal employment in Mozambique

The informal economy accounts for the bulk of employment in many emerging economies. Regulation theory suggests that all economic activity is characterized by a complex combination of formal and informal regulation. Looking at the case of Mozambique, this article explores the pressures towards and against formalization, and the forms regulation can take, drawing on qualitative research based on in‐depth elite interviews and observation. The findings highlight how the State's role in promoting formalization of the informal economy is ambivalent; its approach incorporates both “progressive” elements, which focus on the modernization of regulations and institutions, and “conservative” elements, which inhibit this process of change.     

Business as usual: the UK national daily press and the Occupy Central movement

This essay reviews the coverage of the Occupy Central movement in the UK national daily press from the first notice of the growing movement in July 2013 to the time of writing in January 2015. This is a relatively small subset of the total mentions of Hong Kong in the UK press, which cover a wide range of cultural, leisure, sport, and business stories. Hong Kong is very far from invisible to the UK press in “normal” times but, given that the UK is the former colonial power in Hong Kong, and that the terms under which the territory was returned to China were formalized in an inter-state agreement between the UK and China (the Joint Declaration, ratified in 1985), it is reasonable to assume that developments in the constitutional situation would attract very considerable attention on the part of the UK government. Studies of foreign news suggest that nationally specific factors tend to influence news salience so we would concomitantly expect that the UK newspaper press would devote substantial amounts of space to reporting and discussing the issues raised by these developments.     

Large sample properties and confidence bands for component-wise varying-coefficient regression with longitudinal dependent variable

Longitudinal studies with repeatedly measured dependent variable (out-come) and time-invariant covariates are common in biomedical and epidemi-ological studies. A useful statistical tool to evaluate the effects of covariates on the outcome variable over time is the varying-coefficient regression, which considers a linear relationship between the covariates and the outcome at a specific time point but assumes the linear coefficients to be smooth curves over time. In order to provide adequate smoothing for each coefficient curve, Wu and Chiang ( 1999 ) proposed a class of component-wise kernel estimators and determined the large sample convergence rates and some of the constant terms of the mean squared errors of their estimators. In this paper we calcu¬late the explicit large sample mean squared errors, including the convergence rates and ail the constant terms, and the asymptotic distributions of the kernel estimators of Wu and Chiang ( 1999 ). These asymptotic distributions are used to construct point-wise confidence intervals and Bonferroni-type confidence bands for the coefficient curves. Through a Monte Carlo simulation, wre show that our confidence regions have adequate coverage probabilities. Applying our procedures to a NIH fetal growth study, we show that our procedures are useful to determine the effects of maternal height, cigarette smoking and al¬cohol consumption on the growth of fetal abdominal circumference over time during pregnancy.     

Discounting Compensation for Injuries

The reasons commonly given for discounting future costs and benefits are doubtfully applicable to future injuries: in particular, time preference justifies neither inter- nor intragenerational discounting. The cost of future injuries could be discounted on grounds that a smaller sum, invested at interest, is needed to pay a given level of ex post monetary compensation the further in the future the injury occurs. This effect is offset, however, by the diminishing marginal utility of compensation, if consumption is otherwise increasing. Depending on the elasticity of marginal utility of consumption, on whether consumption is growing at an optimal rate, and on the time period considered, the implicit discount rate may be positive, zero, or negative (even indefinitely so). There is no prospect of conventional discounting dealing appropriately with the cost of injuries to either future or present generations.     

The development and Reform of Social Security Pensions:The Approach of the International Labour Office

The reform and the development of pension schemes are affected by the values society places on the provision of income security in old age and the resources it is prepared to allocate for the purpose. This paper examines those values and the issues arising from them. The objective is to propose reforms which will simultaneously provide full coverage with good governance, prevent poverty in old age, and result in indexed, guaranteed and reliable pensions for those onaverage incomes, all with minimum economic distortion or adverse economic effects. The question of the most appropriate design has to be weighed against these other factors, which will determine not only what is feasible and what is not, but also where the most desirable balance lies. The optimum structure would seem to involve a mix of defined benefit and defined contribution schemes.