Using vulnerability performance indicators to attain food supply chain robustness

High effectiveness and leanness of modern supply chains (SCs) increase their vulnerability, i.e. susceptibility to disturbances reflected in non-robust SC performances. Both the SC management literature and SC professionals indicate the need for the development of SC vulnerability assessment tools. In this article, a new method for vulnerability assessment, the VULA method, is presented. The VULA method helps to identify how much a company would underperform on a specific Key Performance Indicator in the case of a disturbance, how often this would happen and how long it would last. It ultimately informs the decision about whether process redesign is appropriate and what kind of redesign strategies should be used in order to increase the SC's robustness. The applicability of the VULA method is demonstrated in the context of a meat SC using discrete-event simulation to conduct the performance analysis.     

Asymptotic normality of the deconvolution kernel density estimator under the vanishing error variance

Let $X_1,\dots ,X_n$ be i.i.d. observations, where $X_i=Y_i+{\sigma }_n{Z}_i$ and the $Y$’s and $Z$’s are independent. Assume that the $Y$’s are unobservable and that they have the density $f$ and also that the $Z$’s have a known density $k$. Furthermore, let ${\sigma }_n$ depend on $n$ and let ${\sigma }_n\to 0$ as $n\to \infty$. We consider the deconvolution problem, i.e. the problem of estimation of the density $f$ based on the sample $X_1,\dots ,X_n$. A popular estimator of $f$ in this setting is the deconvolution kernel density estimator. We derive its asymptotic normality under two different assumptions on the relation between the sequence ${\sigma }_n$ and the sequence of bandwidths $h_n$. We also consider several simulation examples which illustrate different types of asymptotics corresponding to the derived theoretical results and which show that there exist situations where models with ${\sigma }_n\to 0$ have to be preferred to the models with fixed $\sigma$.     

Precedence tests and Lehmann alternatives

G = F ^k (k > 1); G = 1 − (1−F) ^k (k < 1); G = F ^k (k < 1); and G = 1 − (1−F) ^k (k > 1), where F and G are two continuous cumulative distribution functions. If an optimal precedence test (one with the maximal power) is determined for one of these four classes, the optimal tests for the other classes of alternatives can be derived. Application of this is given using the results of Lin and Sukhatme (1992) who derived the best precedence test for testing the null hypothesis that the lifetimes of two types of items on test have the same distibution. The test has maximum power for fixed κ in the class of alternatives G = 1 − (1−F) ^k , with k < 1. Best precedence tests for the other three classes of Lehmann-type alternatives are derived using their results. Finally, a comparison of precedence tests with Wilcoxon's two-sample test is presented. Received: February 22, 1999; revised version: June 7, 2000     

Dynamic predicting by landmarking as an alternative for multi-state modeling: an application to acute lymphoid leukemia data

This paper considers the problem of obtaining a dynamic prediction for 5-year failure free survival after bone marrow transplantation in ALL patients using data from the EBMT, the European Group for Blood and Marrow Transplantation. The paper compares the new landmark methodology as developed by the first author and the established multi-state modeling as described in a recent Tutorial in Biostatistics in Statistics in Medicine by the second author and colleagues. As expected the two approaches give similar results. The landmark methodology does not need complex modeling and leads to easy prediction rules. On the other hand, it does not give the insight in the biological processes as obtained for the multi-state model.     

Relative Deprivation and Intergroup Prejudice

Using three diverse European surveys, we test the relationship between relative deprivation (RD) and anti-immigrant prejudice. We find that both group relative deprivation (GRD) and individual relative deprivation (IRD) are found primarily among working-class respondents who are politically alienated. We also find that GRD, but not IRD, serves as a proximal correlate of prejudice. IRD's effects on prejudice are largely mediated through GRD. In addition, GRD partially mediates the effects of such distal predictors of prejudice as education and family income. Finally, blaming the victim mediates in part the GRD link with prejudice. These results lead to a socially situated path model of RD's effects on prejudice with public policy implications.     

Value of Information in Closed Loop Supply Chains

We explore the value of information (VOI) in the context of a firm that faces uncertainty with respect to demand, product return, and product recovery (yield). The operational decision of interest in matching supply with demand is the quantity of new product to order. Our objective is to evaluate the VOI from reducing one or more types of uncertainties, where value is measured by the reduction in total expected holding and shortage costs. We start with a single period model with normally distributed demands and returns, and restrict the analysis to the value of full information (VOFI) on one or more types of uncertainty. We develop estimators that are predictive of the value and sensitivity of (combinations of) different information types. We find that there is no dominance in value amongst the different types of information, and that there is an additional pay‐off from investing in more than one type. We then extend our analysis to the multi‐period case, where returns in a period are correlated with demands in the previous period, and study the value of partial information (VOPI) as well as full information. We demonstrate that our results from the single period model (adapted for VOPI) carry‐over exactly. Furthermore, a comparison with uniformly distributed demand and return show that these results are robust with respect to distributional assumptions.     

A WHITER SHADE OF PALE: ON THE POLITICAL ECONOMY OF REGULATORY INSTRUMENTS

We consider an intertemporal policy game between changing governments that differ in their attitudes towards a particular feature of market outcomes, exemplified with environmental pollution. When in power, a government will choose policy instruments and set strictness of regulation with a view to influencing the policy of future, possibly different, governments. We demonstrate that a “brown” government favours emission quotas over effluent taxes, as quotas establish property rights that are costly to reverse. Conversely, a “green” government prefers to regulate by taxes, in order to limit the incentives of future brown governments to ease regulations. Strategic behaviour tends to exaggerate policy differences (making green governments greener and brown governments browner) compared to when such strategic considerations were not an issue. (JEL: D81, D9, H23, L51, Q28, Q38)     

Marriage and Fertility in Russia of Women Born between 1900 and 1960: A Cohort Analysis

In this paper we present a demographic analysisof the marital and fertility careers of Russianwomen, born between 1900 and 1960 and based onindividual retrospective life histories,collected in the most recent (five percent)microcensus of the Russian Federation from1994. It extends an earlier analysis of womenborn between 1910 and 1935. Although politicalevents often had profound effects on themarital life course, none of the observedcrises in Russia has succeeded in exerting adecisive influence on the fertility transition.The fertility decline started late, but takinginto account infant and child mortality thatcontinued to be very high until the fifties,all generations born since 1920 had a completedfertility near or below replacementlevel.