NERJIT: Using Net Requirement Data in Kanban‐Controlled Jumbled‐Flow Shops

The bold lines that have separated the application of specific production planning and control techniques to specific production systems are being blurred by continuous advances in production technologies and innovative operational procedures. Oral communication among dispatchers and production units has given way to electronic communication between production planners and these units by continuous progress in information technologies. Current production literature alludes to the idea that, collectively, these advances have paved the way for application of Just‐In‐Time (JIT) production concepts, which were originally developed for mass production systems, in intermittent production systems. But this literature does not actually consider the possibility. This article presents a modification to JIT procedures to make them more suitable for jumbled‐flow shops. This article suggests providing real‐time information about net‐requirements for each product to each work center operator for setting production priorities at each work center. Simulation experiments conducted for this study show that using Net‐Requirements in JIT (NERJIT) reduces customer wait time by 45–60% while reducing inventory slightly. The analysis of work centers’ input and output stock‐point inventories shows that using the information about net‐requirements results in production of items that are in current demand. NERJIT results in smaller input stock‐point inventory and availability of products with higher priority in the output stock‐points of work centers.     

Consistent estimation for discretely observed Markov jump processes with an absorbing state

For a continuous-time Markov process, commonly, only discrete-time observations are available. We analyze multiple observations of a homogeneous Markov jump process with an absorbing state. We establish consistency of the maximum likelihood estimator, as the number of Markov processes increases. To accomplish uniform convergence in the continuous mapping theorem, we use the continuity of the transition probability in the parameters, the compactness of the parameter space and the boundedness of probabilities. We allow for a stochastic time-grid of observation points with different intensities for each observation process. Furthermore, we account for right censoring. The estimate is obtained via the EM algorithm with an E-step given in closed form. In our empirical application of credit rating histories, we fit the model of Weißbach and Mollenhauer (J Korean Stat Soc 40:469–485, 2011) and find marked differences, compared to the continuous-time analysis.     

Managerial Hostility and Attitudes Towards Unions: A Canada-US Comparison

We use a cross-country survey of attitudes toward work and unions, which includes a sample of managers in both the US and Canada, to explore whether there is greater attitudinal hostility to unions in the U.S. Our estimates indicate that American manager’s attitudes towards unions are, perhaps surprisingly, less hostile than those of Canadian managers. We explain this first finding by the differential effect of perceived union power, which is greater in Canada than the US and which is correlated negatively with union approval. We also find that US managers are less likely to use extreme methods to oppose union organizing drives, implying that the lower union rates in the US as compared to Canada are not likely the result of greater negativity towards unions themselves but rather some other factor or combination of factors. The implication is that if Canadian managers faced the same labor relations playing field as their US counterparts, they would likely find it easier to thwart union certification drives as well. Alternatively stated, Canadian-style labor relations reforms (such as card-check systems or quicker certification votes) could perhaps tip the balance in favor of unions when organizing in the US.     

DO FINANCIAL INCENTIVES AFFECT FIRMS’ DEMAND FOR DISABLED WORKERS?

A number of OECD countries aim to encourage work integration of disabled persons using quota policies. For instance, Austrian firms must provide at least one job to a disabled worker per 25 nondisabled workers and are subject to a tax if they do not. This “threshold design” provides causal estimates of the noncompliance tax on disabled employment if firms do not manipulate nondisabled employment; a lower and upper bound on the causal effect can be constructed if they do. Results indicate that firms with 25 nondisabled workers employ about 0.04 (or 12%) more disabled workers than without the tax; firms do manipulate employment of nondisabled workers but the lower bound on the employment effect of the quota remains positive; employment effects are stronger in low‐wage firms than in high‐wage firms; and firms subject to the quota of two disabled workers or more hire 0.08 more disabled workers per additional quota job. Moreover, increasing the noncompliance tax increases excess disabled employment, whereas paying a bonus to overcomplying firms slightly dampens the employment effects of the tax.     

Grassroots Support Organizations and Transformative Practices

ABSTRACT

This essay theorizes grassroots support organizations (GSOs) as empowerment-oriented development nongovernmental organizations (NGOs) and grassroots support as a growing field of community-based practice. It offers a conceptual definition of GSOs; specifies their organizational features, functions, and goals; and differentiates them from other public and private intermediary organizations. It also details the activities carried out by GSOs and suggests how these cohere into a model of grassroots support. The article discusses the challenging issues of financing, accountability, and scale faced by GSOs. Finally, it establishes the relevance of social work to grassroots support and GSOs as fields of study and practice.     

Pathological Gambling and Treatment Outcomes for Adults Age 50 or Older in Methadone Maintenance Treatment

This study examined the relationship of pathological gambling to negative treatment outcomes for methadone maintenance patients aged 50 or older. The study included 130 methadone maintenance patients. Pathological gambling was determined using the Lie-Bet, a screen for pathological gambling; the outcomes were remaining in treatment and negative urine screens for drug use. Twenty percent of the sample identified as pathological gamblers. Pathological gambling was unrelated to remaining in treatment or negative urine screens. Although pathological gambling had no adverse influence on these treatment outcomes, the prevalence of pathological gambling suggests that screening for it may provide insights about other concerns.     

Providing social security in a context of change: Experience and challenges in Latin America

Over the past two decades Latin America has experienced major demographic, economic and social changes. The trend towards accelerated ageing of the population in most countries, together with the financial restrictions faced by social protection systems, has brought sweeping changes in pension programmes. The new demographic and labour context presents challenges for these new programmes which, unless they make the necessary adaptations, will definitely be unable to attain their stated objective of providing universal coverage and eliminating poverty in old age. This article offers a general discussion of the processes that the region is undergoing, as well as the limitations and challenges imposed by existing welfare systems. Finally, it examines the options available to retain the objective of universal coverage and thus ensure the economic needs of the elderly population.     

Redistribution and labour supply

This paper explores the effect of personal income taxes on redistribution when labour supply reactions are taken into consideration. The results indicate that the classical non-behavioural results on redistribution are not necessarily satisfied in a more general behavioural framework. In this respect, it is shown that the relevant transition to measure redistribution is not the transition from the initial post-tax to the final post-tax income distribution, but rather from the more precise initial pre-tax to the final post-tax income distribution. In addition, the necessary and sufficient conditions to ensure redistribution in this wider setting are postulated, which helps determine the behavioural bias under alternative tax and labour supply models. This shows that the functional specification of labour supply may also affect the results.     

Approximation algorithms for <Emphasis Type="Italic">k</Emphasis>-level stochastic facility location problems

In the k-level facility location problem (FLP), we are given a set of facilities, each associated with one of k levels, and a set of clients. We have to connect each client to a chain of opened facilities spanning all levels, minimizing the sum of opening and connection costs. This paper considers the k-level stochastic FLP, with two stages, when the set of clients is only known in the second stage. There is a set of scenarios, each occurring with a given probability. A facility may be opened in any stage, however, the cost of opening a facility in the second stage depends on the realized scenario. The objective is to minimize the expected total cost. For the stage-constrained variant, when clients must be served by facilities opened in the same stage, we present a \((4-o(1))\)-approximation, improving on the 4-approximation by Wang et al. (Oper Res Lett 39(2):160–161, 2011) for each k. In the case with \(k=2,\,3\), the algorithm achieves factors 2.56 and 2.78, resp., which improves the \((3+\epsilon )\)-approximation for \(k=2\) by Wu et al. (Theor Comput Sci 562:213–226, 2015). For the non-stage-constrained version, we give the first approximation for the problem, achieving a factor of 3.495 for the case with \(k = 2\), and \(2k-1+o(1)\) in general.