Engineer-to-order (ETO) production planning and control: an empirical framework for machinery-building companies

This paper illustrates the results of an empirical study involving 21 engineer-to-order (ETO) companies, operating in the machinery-building industry. The study investigates the needs and requirements of such companies in terms of software support for governing the businesses, with particular emphasis on production planning and control (PPC) processes. An empirical analysis investigated two main aspects: (i) the set of business activities performed by the companies in the analysed industry and (ii) the relevant, high-level software functionalities required for the execution of such activities. As an answer to the observed compelling need for reviewing the general approaches to PPC in machinery-building companies, we develop an empirical, high-level production planning and scheduling reference framework, encompassing all the activities involved in the order fulfilment process.     

Improving productivity of automated tissue converting lines: an empirical model and a case study

This study is focused on minor stoppages as sources of variance within automated production lines in industrial environments, and it suggests the handling of the problem through a combined phenomenon–mechanism analysis and simulation approach. The resulting seven-step methodological pattern has been applied to a real-life case study of a tissue converting line: the product type and the machine speed have been identified as causal factors for minor stoppages and the wrapper machine has been chosen to exemplify the methodology.

Results point out that the speed of the wrapping machine–which allows the daily throughput of line to be maximized–changes when products change, thus highlighting a trade off between minor stoppages and wrapper speed. However, in some other cases, minor stoppages are more detrimental than the machine speed is useful.     

Resource Allocation in Integrated Preoperational and Operational Management of Natural Hazards

The management of natural hazards occurring over a territory entails two main phases: a preoperational —or pre-event—phase, whose objective is to relocate resources closer to sites characterized by the highest hazard, and an operational —during the event—phase, whose objective is to manage in real time the available resources by allocating them to sites where their intervention is needed. Obviously, the two phases are closely related, and demand a unified and integrated treatment. This work presents a unifying framework that integrates various decisional problems arising in the management of different kinds of natural hazards. The proposed approach, which is based on a mathematical programming formulation, can support the decisionmakers in the optimal resource allocation before (preoperational phase) and during (operational phase) an emergency due to natural hazard events. Different alternatives of modeling the resources and the territory are proposed and discussed according to their appropriateness in the preoperational and operational phases. The proposed approach can be applied to the management of any natural hazard and, from an integration perspective, may be particularly useful for risk management in civil protection operations. An application related to the management of wildfire hazard is presented.     

Tax evasion, tax morale and policy maker's effectiveness

This paper aims to show that aggregate tax evasion may be largely explained by tax morale and that tax morale is dependent on the taxpayers’ intrinsic attitudes to honesty and social stigma. The theoretical hypothesis is that these attitudes are influenced by the taxpayers’ perceptions of the size of tax evasion as well as by their perceptions of the policy maker's effectiveness in exercising control over the relevant macroeconomic variables and safeguarding the interests of citizens. Applying Gordon's [Gordon, J.P.F., 1989. Individual morality and reputation costs as deterrents to tax evasion. European Economic Review 33(4), 797–805] framework, a dynamic model of aggregate tax evasion is proposed whereby multiple equilibria may emerge. Econometric analysis on Latin American countries supports the assumptions made in the model.     

The economists and the primitive societies: A critique of economic imperialism

The extension of economics to topics that lie outside its classical domain is known as ‘economic imperialism’. But there are territories of social science that persist to be largely intractable using the postulates of economic theory: the anthropological subject of primitive societies represents one such territory. This paper describes and discusses the representation of primitive societies by economists from the proto-imperialist model of Smith to the imperialist Posner's model. It maintains that (a) the economists’ attempt at interpretation is highly unsatisfactory and (b) it is possible to offer a different representation of the primitive societies, one more coherent with the anthropological and ethnographical data, and able to show the inadequacy and insubstantiality of many economic categories when applied to those societies.     

Interpenetrating subsampling regression estimation with or without jackknifing

In this paper four regression estimators are considered for a finite population total based on interpenetrating subsamples, two of which are with jackknifing and the other two are without jackknifing. Both theoretical and empirical comparisons of the four proposed estimators are done with respect to bias, variance and mean square error.     

Online control by attributes in the presence of classification errors with variable inspection interval

ABSTRACT

The procedure for online control by attribute consists of inspecting a single item at every m items produced (m ≥ 2). On each inspection, it is determined whether the fraction of the produced conforming items decreased. If the inspected item is classified as non conforming, the productive process is adjusted so that the conforming fraction returns to its original status. A generalization observed in the literature is to consider inspection errors and vary the inspection interval. This study presents an extension of this model by considering that the inspected item can be rated independently r (r ≥ 1) times. The process is adjusted every time the number of conforming classifications is less than a, 1 ≤ a ≤ r. This method uses the properties of an ergodic Markov chain to obtain the expression for the average cost of this control system. The genetic algorithm methodology is used to search for the optimal parameters that minimize the expected cost. The procedure is illustrated by a numerical example.     

A multivariate logit model with marginal canonical association

In this work, a generalization of the Goodman Association Model to the case of q, q > 2, categorical variables which is based on the idea of marginal modelling discussed by Gloneck–McCullagh is introduced; the difference between the proposed generalization and two models, previously introduced by Becker and Colombi, is discussed. The Becker generalization is not a marginal model because it does not imply Logit Models for the marginal probabilities, and because it is based on the conditional approach of modelling the association. The Colombi model is only partially a marginal model because it uses simple logit models for the univariate marginal probabilities but is based on the conditional approach of modelling the association. It is also shown that the maximum likelihood estimation of the parameters of the new model is feasible and, to compute the maximum likelihood estimates, an algorithm is proposed, which is a numerically convenient compromise between the constrained optimization approach of Lang and the straightforward use of the Fisher Scoring Algorithm suggested by Glonek–McCullagh.Finally, the proposed model is used to analyze a data set concerning work accidents which occurred to workers at some Italian firms during the years 1994–1996.