ON THE SOLUTION OF SPATIAL EQUILIBRIUM MODELS*

Recent advances in mathematical programming methods and computing technology have the potential for overcoming the many formidable barriers to the widespread solution of nonlinear spatial models. In particular, the recent public availability of the software package MINOS/AUGMENTED has major implications for both policy and theoretical research involving spatial models. In this paper, mathematical programming formulations of two highly nonlinear spatial models are provided, model solutions presented, and associated computational experience discussed. In addition, related work is discussed briefly and suggestions are advanced concerning the potential role of the package in furthering the objectives of this related work. Subject Areas: Mathematical Programming, Transportation, and Urban and Regional Planning.     

An Evaluation of Capacity Sensitive Order Review and Release Procedures in Job Shops

We investigate the performance of capacity-sensitive order review and release (ORR) procedures in job shop environments that have not been previously explored. Previous research has ignored the case of job shops which must perform to very tight due-dates because of time-sensitive customers. We propose and test a new capacity sensitive ORR procedure called path based bottleneck (PBB) in such environments, along with the modified infinite loading (MIL) procedure which has been shown to work well in several studies. We compare the performance of these two controlled release rules with that of immediate release rule under different conditions of capacity utilization and customer specified exogenous duedates. Our results indicate that PBB performs well in lowering total costs when due-dates are tight, while MIL is a better procedure with relatively loose to medium due-dates. We also show that in many cases, the shortest processing time (SPT) dispatching rule is a superior performer than a due-date based rule like critical ratio (CR); a conclusion which is contrary to the existing research in this area. In addition, the shop floor control policies recommended are shown to be sensitive to the cost structure of the firm. The managerial implications of this research in providing effective shop floor control in job shops operating under tight due-date conditions are also discussed.     

Unemployment Stigma and Multiple Labour Market Equilibria: A Social-Psychological Interpretation of Hysteresis

ABSTRACT: This paper supplements a simple one period non-shirking efficiency wage model with behavioural assumptions drawn from the social-psychological literature. A model of social interaction is developed in which the status associated with various labour market options yields implications for the shape of the non-shirking constraint and, thereby, for the number and type of labour market equilibria. The significance of such a finding for the existence of unemployment hysteresis is explored.     

Stochastic and Intransitive Behavior in a State-Preference Model of Asset Choice*

Most models of investor behavior assume a time-state independent utility function and result in a deterministic solution where a given set of inputs uniquely specifies the decision. In contrast, a state preference model using a time-state dependent utility function is derived in this paper. The model allows the investment choice decision to be analyzed in a game theoretic context. The general solution is a mixed strategy which allows for a probabilistic interpretation of the decision. The approach presented in this paper can accommodate anomalies such as intransitivity of preference and satisficing as rational behavior. An example of a possible implementation is given along with interpretations of the outcomes.     

Resolutions: Working with Families Where Responsibility for Abuse is Denied

Current thinking suggests that little productive work can be undertaken with families where serious physical or sexual abuse of children has occurred in the absence of a clear acceptance of responsibility for that abuse. This means that children are often removed from their families because of the perceived risks, with the disadvantages that being looked after in local authority care often brings. Alternatively, children may be left in the same environment where serious abuse has taken place with little or no work being undertaken with the family. Either approach fails children, especially those who have made clear and believable allegations in the hope of bringing about a process of change and protection. This article describes the work of a pilot project at the Avon NSPCC in Bristol working with families where the alleged abuser disputes responsibility for maltreating the child. Key to this approach is the support of the non-abusing carer and the child/ren while the concerns of the professional agencies are addressed. The work has two main phases. The first looks for structural change in the organization of family life. The second part asks carers to role-play a ‘similar’ hypothetical family where child abuse has been established. This enables difficult issues raised by the abuse to be addressed and provides an opportunity for carers to express thoughts and feelings to their partner regarding abuse without the seriousness of the concerns being lost.     

Addiction science and the perception of freewill

Do people think individuals with Substance Use Disorder (SUD) have freewill? How does addiction science inform views on the issue? We distinguish between two senses of freewill: 1) libertarian freewill , in which freedom turns on a particular metaphysical conception of action (sometimes operationalized as “could have done otherwise”), and 2) compatibilist freewill , in which freedom depends on the relation between the actor's psychology and her actions (e.g., “was the act what she wanted to do?”). We argue that, in different ways, scientific accounts can impact conceived freewill by linking addictive behavior to mechanisms that observers view as peripheral to the actor ( motivation modularity) . While a variety of impacts on conceived compatibilist freewill are plausible, we argue that contemporary addiction science has no direct bearing on conceived libertarian freewill. Addiction science may, however, indirectly impact conceived libertarian freewill by priming an explanatory framework in which intention is superfluous (especially materialism).     

Opting out of workers’ compensation: Non-subscription in Texas and its effects

Journal of Risk and Uncertainty - Texas is the only state that does not mandate that employers carry workers’ compensation (WC) insurance coverage. In place of traditional WC, companies can...     

Changement technologique et emploi au Brésil,en Colombie et au Mexique: quels sont les travailleurs les plus affectés?

L'analyse, axée sur les tâches, de la structure de l'emploi urbain du Brésil, de la Colombie et du Mexique montre que celui-ci a nettement diminué entre 2002 et 2015 dans des professions semi-qualifiées et augmenté dans les professions faiblement et fortement qualifiées. La décomposition des résultats suggère que le déclin de l'emploi des secrétaires et des sténographes s'explique entièrement par les changements intrabranche (hypothèse de «routinisation»), tandis que dans la conduite des machines et l'artisanat l'explication tient aux changements interbranches. Sous l'angle sociodémographique, le changement technologique affecte négativement les femmes, mais il profite aux travailleurs plus jeunes et plus instruits.