A decision support system for a third-party coordinator managing supply chain with demand uncertainty

Global supply chains reduce cost but increase lead times, complexities and uncertainties. Retailers in consumer products industry are getting shorter lead time to respond to market demand. To meet this challenge, many rely on third party supply chain managers (SCMs) for economically supplying required quantities of finished products quickly. However, due to shorter ‘time to market’, the SCM has to procure raw materials and start production process based on expected demand. Since SCM absorbs financial penalties associated with under- and over-estimation of demand from retailer, finding an optimal production lot size and product customisation strategy are essential to an SCM's operation. We develop a profit maximisation model and provide a close-form solution that allows an SCM to calculate optimal production lot size. The model is used to examine profitability of postponing product customisation. Finally, the effect of demand variation on SCM's profitability is explored.     

Conceptualising and Categorising Child Abuse Inquiries: From Damage Control to Foregrounding Survivor Testimony

Testimony before inquiries into out‐of‐home care that have taken place in many countries over the last twenty years has severely disrupted received ideas about the quality of care given to children in the past. Evidence of the widespread abuse of children presented before recent inquiries internationally gives rise to the question: why didn’t we know? Part of the answer lies in the changing forms and functions of inquiries, whose interests they serve, how they are organised and how they gather evidence. Using as a case study, a survey of historical abuse inquiries in Australia, this article explores the shift to victim and survivor testimony and in so doing offers a new way of conceptualising and categorising historical child abuse inquiries. It focuses less on how inquiries are constituted or governed, and instead advances an historically contextualised approach that foregrounds the issue of who speaks and who is heard.     

A note on the generalisation of cochran’s theorem

Khatri (1968) has extended Cochran’s theorem (1934) to matrices which are not necessarily symmetric. An alternative proof of the theorem is furnished here with some generalization with respect to one of Khatri’s conditions.     

Multi-product lot scheduling with backordering and shelf-life constraints

In this paper, we revisit the economic lot scheduling problem (ELSP), where a family of products is produced on a single machine, or facility, on a continual basis. Our focus is on the determination of a feasible production schedule, including the manufacturing batch size of each item. We assume that total backordering is permissible and that each of the products has a limited post-production shelf life. Several studies examining this problem have suggested a rotational common cycle approach, where each item is produced exactly once every cycle. To ensure schedule feasibility, we resort to the technique of reducing individual production rates and allow the flexibility of producing any item more than once in every cycle, in conjunction with appropriate timing adjustments. In order to solve this more generalized model, which is NP hard, we suggest a two-stage heuristic algorithm. A numerical example demonstrates our solution approach.     

The population characteristics of the East African red legged diplopodMetiche tanganyciense Kraus (Diplopoda: Spirobolidae)

Summary A marked variation exists in the numbers and distribution of East African red legged millipedeMetiche tanganyciense Kraus on the surface and in the lower layer (15 cm) of the soils. Stadia 5 cm and lesser in length are found in the lower layer and those 5 cm and above on the surface soil. Adults are common in varying numbers in both the habitats. It is suggested that after becoming surface active during March–August, and mating, adults migrate to lower layer during September to oviposit. Eggs and early developmental stages are passed here, and when they are 5 cm in length, the stadia move to the surfface soil to complete their development. In keeping with this behaviour, spatial distribution of the adults may change from non-aggregation on surface soil to aggregation in the lower layer. The simulataneous presence of adults and developing stadia in the two habitats suggests and overlapping of generations. This investigation was done while I was in the Department of Entomology, University of Nairobi.     

A Simple Univariate Outlier Identification Procedure Designed for Large Samples

A simple univariate outlier identification procedure is presented for the detection of multiple outliers in large and moderate sized data sets. This procedure is a modification of the well-known boxplot outlier-labeling rule. Critical values are easy to obtain for the large sample case for a variety of useful distributions, including the normal, t, gamma, and Weibull. Simple adjustment formulas and graphs are provided for handling smaller samples. Basic probability properties are obtained mathematically and through simulation. Two data sets illustrate the procedure's application as a simple and effective screening tool for both moderate and large-sized univariate samples.     

Fuzzy preferences and Arrow-type problems in social choice

There are alternative ways of decomposing a given fuzzy weak preference relation into its antisymmetric and symmetric components. In this paper I have provided support to one among these alternative specifications. It is shown that on this specification the fuzzy analogue of the General Possibility Theorem is valid even when the transitivity restrictions on the individual and the social preference relations are relatively weak. In the special case where the individual preference relations are exact but the social preference relation is permitted to be fuzzy it is possible to distinguish between different degrees of power of the dictator. This power increases with the strength of the transitivity requirement.For comments on an earlier version of the paper I am indebted to an anonymous referee, an anonymous member of the Board of Editors and to participants in the 1991 Annual Conference of the Indian Econometric Society at North Bengal University, India. However, I retain sole responsibility for any error(s) that the paper may contain.     

Fatigue effects of noise on aeroplane mechanics

Abstract

Subjective fatigue and reaction time performance were measured in a group of 24 aeroplane mechanics, during 1 week of high noise exposure and 1 week of low noise exposure. Subjective ratings were collected before and after each work day. On the last day of each week subjects also completed a reaction time task before and after work. The mechanics felt more sleepy and less energetic during the high noise week. This effect was most evident towards the end of the day and there was a build-up of the effect during the week. Reaction times were prolonged during the high noise week. Possible confounding factors are discussed and found to be less likely explanations of the effects.