Efficiency and effectiveness in railway performance using a multi-activity network DEA model

This paper provides a multi-activity network data envelopment analysis model that represents both production and consumption technologies in a unified framework. The model is applied to simultaneously estimate passenger and freight technical efficiency, service effectiveness, and technical effectiveness for 20 selected railways for the year 2002. The results show that these measures differ significantly. Since the multi-activity network data envelopment analysis models the reality of railways’ operations, one can gain further insights from the estimated results and thus propose strategies for improving operational performance.     

Comment

In several anonymous questionnaire studies of college students, marijuana use has been reported to affect sexual behavior. In general, these studies show that marijuana smoking enhances sexual pleasure and increases sexual desire. Marijuana use has also been associated with more frequent sexual activity and an increased number of sexual partners. The purpose of this study was to determine the perceived effects of marijuana use on the sexual behavior and sexual practices of a sample of regular marijuana .users. In contrast to other studies, subjects were not drawn exclusively from college student populations and were interviewed rather than given a questionnaire. Results, in general, confirm results of previous studies. Subjects were primarily heterosexual and sexually active. Men were more likely than women to have had multiple sexual partners. Over two thirds reported increased sexual pleasure and satisfaction with marijuana. Increased desire for a familiar sexual partner was reported by about one half. The sensations of touch and taste were particularly enhanced by marijuana. Many felt marijuana was an aphrodisiac. Marijuana use in relation to initiation of sexual activity was also assessed. Although drug use occurred prior to first intercourse for about one third of the men and women, alcohol, not marijuana, was most frequently used in this context. Most had used marijuana as a preparation for intercourse on occasion, and 20% did this on a regular basis. Possible explanations for these effects are briefly discussed.     

Searching for belonging and confronting exclusion: a person-centred approach to immigrant settlement experiences in Canada

ABSTRACT

Drawing on an analysis of three immigrant narratives, this paper employs a person-centred approach to immigrant integration in Canada. It examines how immigrants interpret the inclusions/exclusions that mark their integration experience and the consequences these experiences have on their social identities and sense of belonging. Analysis demonstrates that for immigrants a sense of belonging does not grow in a linear fashion; rather, it grows, stalls, dissipates and/or flourishes in relation to the ties and identifications that immigrants are enabled to forge. Broader structural and historical forces prefigure immigrant inclusion and exclusion in Canada in ways that reflect a hierarchy of migration and belonging. We argue that a recognition of Canada’s ‘hierarchies of belonging’ and the multidimensional nature of social inclusion/exclusion complicate integration metaphors that flatten the uneven social terrain of immigrant belonging.     

Deservingness in the eye of the beholder: A vignette study on the moderating role of cultural profiles in supporting activation policies

People support welfare policy if its beneficiaries are perceived as deserving of support. This study found that individuals’ cultural worldviews play a role in assessing the deservingness of welfare recipients. We investigated whether four different cultural profiles find some beneficiaries to be more deserving than others and how this relates to support for social rights (welfare benefit, retraining, job coach) and obligations (mandatory volunteering). A Dutch vignette experiment showed that reasons for supporting social rights differ between people with different cultural profiles: equality advocates grant support if beneficiaries are needy, while the centre and trusting groups do so when beneficiaries reciprocate. We found that irrespective of deservingness, people with equality‐advocating and trusting profiles tend to be more supportive of social rights, whereas socially discontented citizens tend to emphasise the importance of obligations. In general, obliging beneficiaries to do volunteer work was deemed appropriate by almost all respondents in the study, whereas their cultural values determined the ways in which they considered social rights to have been earned.     

Scheduling dedicated jobs with variative processing times

We consider the following optimization problem. There is a set of \(n\) dedicated jobs that are to be processed on \(m\) parallel machines. The job set is partitioned into subsets and jobs of each subset have a common due date. Processing times of jobs are interconnected and they are the subject of the decision making. The goal is to choose a processing time for each job in a feasible way and to construct a schedule that minimizes the maximum lateness. We show that the problem is NP-hard even if \(m=1\) and that it is NP-hard in the strong sense if \(m\) is a variable. We prove that there is no approximate polynomial algorithm with guaranteed approximation ratio less than 2. We propose an integer linear formulation for the problem and perform experiments. The experiments show that the solutions obtained with CPLEX within the limit of 5 min are on average about 5 % from the optimum value for instances with up to 150 jobs, 16 subsets and 11 machines. Most instances were solved to optimality and the average CPLEX running time was 32 s for these instances.     

The Value of Information for Managing Retail Inventory Remotely

An important difference between both manufacturing and wholesaling vs. retail is the information available concerning inventory. Typically, far less information characterizes retail. Here, an extreme environment of information shortfall is examined. The environment is technically termed “unattended points of sale,” but colloquially called vending machines. Once inventory is loaded into a machine, information on demand and inventory level is not observed until the scheduled reloading date. Technological advances and business process changes have drawn attention to the value of information (VOI) in retail inventory in many venues. Moreover, technology is now available that allows unattended points of sale to report inventory information. Capturing the value of this information requires changes in current business practice. We demonstrate the value of capturing information analytically in an environment with restrictive demand assumptions. Experiments in an environment with realistic demand assumptions and parameter values show that the VOI depends greatly on operating characteristics and can range from negligible effects to increasing profitability 30% or more in actual practice.     

Multivariate analysis for the two-period repeated measures crossover design with application to clinical trials

Multivariate analysis techniques are applied to the two-period repeated measures crossover design. The approach considered in this paper has the advantage over the univariate analysis approach proposed recently by Wallenstein and Fisher (1977) that the former does not require any specific structure on the variance-covariance matrix of the repeated measures factor. (It should be noted that sums and differences of observations over periods are used for all tests. Therefore, there are two matrices under consideration, one for sums and one for differences.) Tests of significance are derived using the Wilks? criterion, and the procedure is illustrated with a numerical example from the area of clinical trials.