Analysing job creation effects of scaling up infrastructure spending in South Africa

In a first for South Africa, this article draws on literature on infrastructure productivity to model dynamic economy-wide employment impacts of infrastructure investment funded with different fiscal tools. Using a dynamic computable general equilibrium model, the South African investment plan is modelled, given the infrastructure externality. Alternative fiscal scenarios to finance the policy are modelled in the article. In the long run, unemployment decreases for all types of workers under one of the scenarios. In the short run, only elementary occupation workers benefit from a decrease in unemployment; for the rest, unemployment rises.     

Constructing trident, reinforcing the network

This paper draws upon the traditions of social construction of technology and actol-net work theory, in an attempt to show that just as these approaches have been used to expose the contingent nature of 'technical' change, they can also be adapted to show the contingency of the 'social' aspects of technology, such as redundancy and technological unemployment, which have in recent years assumed an almost unassailable sense of inevitability. This process is begun when technology is viewed as a social network. Then focusing on the production phase in the life cycle of a technical system, it is argued here that the,jettisoning of both people and technical resources from the network may get presented as part of technology's 'natural' trajectoly, but is often part of the (socio-technical) 'heterogenous engineering' necessary for the stabilization of that technology. and consequently need not be seen as inevitable.     

Conservation Through Commercialisation

The author recounts from first-handknowledge and experience the attempts by Mariculture to form the green sea-turile, and the opposition encountered from environmentolists and other.     

Women in hotel and catering management in the U.K.

Traditionally management has been a function dominated by males in society but currently, due to a number of changes in the environment, many more women are entering into this area. It is envisaged that this trend will continue in the future. The paper commences with a review of the literature examining the background of the issue, and proceeds to highlight some of the reasons contributing to female under-representation in management. The paper concludes by proposing a strategy towards rectifying the balance in the hotel and catering industry.     

Optimal maintenance center inventories for fault-tolerant repairable systems

In many military and commercial contexts, complex equipment which is expected to perform very reliably is often designed to be fault-tolerant, that is, able to function although some of the parts have failed. A popular fault-tolerant design is the m-out-of-n system, where there are n identical parts, at least m of which must be functional for machine operation. Complex equipment of this type often undergoes scheduled maintenance overhauls at regular intervals during which all failed components are replaced. Failure to have replacements on hand for failed parts requires emergency measures at premium cost. When repairable parts are highly reliable and expensive, both holding and shortage costs are high. A reasonable objective is to choose initial spares inventory to minimize the sum of holding costs and expected shortage costs.We first develop a model to determine the optimal repairable parts inventory for a maintenance center servicing machines containing a single m-out-of-n system. The model is then extended to handle a related problem, finding optimal maintenance center inventories for machines containing several m-out-of-n systems of different parts, minimizing total expected costs subject to a constraint on total inventory investment.We assume that there is a fleet of machines, which experience identical workloads. There is a cycle time of T days between overhauls for an individual machine. A machine arrives at the maintenance center for overhaul each day. At the overhaul, all failed parts are removed and sent to a repair shop, from which they eventually return to the maintenance center to be used again as spares. The total number of spares undergoing repair and on hand is a constant. There are no backorders; if the number on-hand spares is insufficient to meet demand at an overhaul, a shortage penalty is assessed which depends on the number and type of spares required.While computing holding costs is straightforward, computing expected shortage costs is more complex. Expected shortage costs are dependent upon several factors, including component failure rates, the values of m and n, part repair rates, and the initial number of spares on hand. We assume that the system of interest is well specified, so that the parameters of the model are known except for the number of initial spares of each type, which are the decision variables. We model the on-hand inventory of each type of part as a Markov chain with the number of spares on hand at the end of each day as the states, under the assumptions that failure rates are constant and repair times follow independent exponential distributions. We then calculate the steady-state probabilities of stockout of various numbers of spares, as a function of the initial spares inventory. The expected shortage costs for a given type of spare may then be calculated by finding the product of the penalty cost for lacking p spares and the probability of lacking p spares and summing over all possible p values.Solutions to the problem of finding optimal initial inventory level for a machine containing a single m-out-of-n system may be found easily by enumeration. Solutions to the constrained problem where the machine contains several independent m-out-of-n systems, may be found by dynamic programming. Sensitivity analysis of costs to changes in the inventory investment constraint is clear, and computational effort is reasonable. A simple example is included to illustrate the solution method for both problems.     

a fire inspector calls

Mike Fisher, an Institute of Economic Affairs' trustee and director of Whale Tankers, explains what happened when the fire inspector called on the home of the great British whale.     

Software engineering standards: the 'formal methods debate' in the uk

This paper traces the evolution of two standards, Def Stan 00-55 and 00-56, regualtin the identification and productin of safety-critical software for defence applications, issued by the Ministry of Defence (MoD) as interim standards in 1991. The standards—00-55, in particular—have become an important forum for articulating the interests of those who work in the UK safety-critical software engineering field; a debate which has largely revolved around the intergral role 00-55 demands for formal methods of sofware development for safety-critical functions or components. In recounting the stor of their gestation within the MoD during the early 1980s; their controversial release in draft form in 1989; and their subsequent second release as interim standards in 1991, the aim has been to illuminate some of the current 'politics' of formal methods of software production, and to consider how the standards are reshaping the discipline of software engineering.