Simple policies in the economic lot scheduling problem with zero setup costs

The economic lot scheduling problem is analysed for the case when the cost of setups, but not their duration, is assumed to be zero. This would be the case when setups are performed by the machine operators, or when management's goal is holding-cost reduction. Theoretical results are presented describing when the common cycle solution of producing one lot of every item every cycle is optimal or near optimal. Computational results using simulated data are then presented which show that the common cycle solution is nearly optimal in a wide range of practical situations.     

Positivism and ‘Functional Theory’ in the Thought of Karl Polanyi, 1907–1922

Karl Polanyi is the author of a modern social science classic, The Great Transformation, as well as a number of well‐known and widely debated essays collected in Trade and Market in the Early Empires and Primitive, Archaic and Modern Economies. These texts were researched and written either during his second exile in 1930s Britain or in wartime or post‐war North America. Not so well known, however, are his Hungarian writings from the 1910s. Until recently, very few of these had been republished or translated, although this is in the process of being rectified [ Gareth Dale (forthcoming) : Karl Polanyi: The Hungarian Writings]. With reference to new translations of his Hungarian writings, to interviews with his daughter, Kari Polanyi‐Levitt, as well as to biographical essays by György Litván, Évá Gábor, Endre Kiss, and Zoltán Horváth, this article explores his early influences, drawing attention in particular to his flirtation with and then violent reaction against philosophical materialism and ‘objectivist’ sociology, his appreciation of Ernst Mach’s positivism, and his adherence to the ‘functional theory’ of contemporary Guild Socialism.     

Estimating quantiles using optimally selected order statistics

This expository paper deals with the linear estimation of quantiles of location-scale families of distributions using a few selected order statistics.The general theory for the problem i s reviewed for the exact as well as the asymptotic cases.     

Estimation of quantiles of exponential and double exponential distributions based on two order statistics

Asymptotically best linear unbiased estimators (ABLUE) of quantiles, x^., in the two-parameter (location-scale) exponential and double exponential families are obtained as linear combinations of two suitably chosen order statistics. Exact formulae for the linear combinations are given as functions of £. The derived estimators in both cases compare favorably with the usual nonparametric estimator. Also, in the exponential case the derived estimator compares favorably with the Sarhan-Greenberg BLUE based on a complete sample     

The prevalence and incidence of HIV among injection drug users: A five year panel study

Six hundred and one injection drug users (IDUs) who attended drug treatment programs in Miami, Florida, were enrolled in a panel study to determine the prevalence and incidence of human immunodeficiency virus (HIV) and associated risk factors. A structured questionnaire which elicited injection and sexual behaviors was administered and blood was obtained by venipduncture. All participants were reassessed at six month intervals for 5 years. The baseline prevalence of HIV was 16.3%. African–Americans had a prevalence of HIV (37.1%) that was significantly higher than that of non-Hispanic whites (7.6%); the prevalence of HIV among Hispanics was 27.2%. Persons who were more than thirty years of age were more likely to test HIV positive (17.8%) than were younger participants (9.7%). The annual incidence per 1000 person-years of exposure for the 503 initially seronegative participants was consistently low for each year of the study. The 5 year incidence was 4.1 per 1000 person years; 7.5 for men and 1.7 for women, 7.5 for African–Americans and 3.8 for non-Hispanic whites. No Hispanic participants seroconverted. Multivariate logistic techniques were used to identify the independent risk factors for HIV prevalence. Earlier injection, ethnicity, and income were independently associated with HIV serostatus. A history of a sexually transmitted disease was marginally associated with HIV prevalence. Low incidence probably is a function of the reduction of risk behavior that occurred over the course of the study and the stage of the epidemic.     

Algorithms of Oppression: How Search Engines Reinforce Racism

SUMMARY

This paper presents a literature review of social work programs' distance education evaluation studies with an emphasis on the strengths distance education programs offer to students relative to standard programs. The authors discuss quality issues in relation to teaching and learning in distance education programs with a panel of distance learners who will discuss their experiences.     

Identifying Themes Regarding the Benefits and Limitations of Caregiver Support Group Conversations

Support groups continue to be one of the most needed and desired forms of help for family caregivers to persons with dementia. Though the effects of caregiver support group participation have been examined, the benefits and limitations of the dynamics of support group conversations have been neglected. This study focuses on the perceived consequences of group dynamics. Three themes—balance, sameness, and individuality—emerged through analysis of open-ended interviews with support group members following observations of their meetings. The consequences of these themes are illustrated with a case study and the implications of these themes for practitioners are discussed.     

The case for small area microdata

Summary.  Census data are available in aggregate form for local areas and, through the samples of anonymized records (SARs), as samples of microdata for households and individuals. In 1991 there were two SAR files: a household file and an individual file. These have a high degree of detail on the census variables but little geographical detail, a situation that will be exacerbated for the 2001 SAR owing to the loss of district level geography on the individual SAR. The paper puts forward the case for an additional sample of microdata, also drawn from the census, that has much greater geographical detail. Small area microdata (SAM) are individual level records with local area identifiers and, to maintain confidentiality, reduced detail on the census variables. Population data from seven local authorities, including rural and urban areas, are used to define prototype samples of SAM. The rationale for SAM is given, with examples that demonstrate the role of local area information in the analysis of census data. Since there is a trade-off between the extent of local detail and the extent of detail on variables that can be made available, the confidentiality risk of SAM is assessed empirically. An indicative specification of the SAM is given, having taken into account the results of the confidentiality analysis.