On bespoke decision-aid under risk: the engineering behind preference elicitation

International audienceDecision-aid as developed from the late Fifties to the mid-Seventies has introduced a substantial change in the previous practice of OR. The spirit of this new deal of a bespoke decision-aid has indeed been that the decision maker’s own preferences, including risk tolerance and attribute selection, as opposed to the standardized goals or discretionarily assigned objectives of the analyst, should be paramount in selecting the most satisfactory strategy. But this way of implementing decision-aid has not received in practice as wide an application as it should have, due to some unduly persistent although erroneous objections. Eliciting the preferences of someone else has thus been regarded as some logically impossible task. The present article argues that such suspicions are today obsolete and that most of the evoked biases or objections can be overcome by using methods of elicitation ignored by textbooks. In particular, the article presents a complete set of non-parametric methods that avoid the above biases and objections. It suggests that a number of fields of application, in wealth management and finance as well as in human resources management and managerial choices, urgently call for such genuinely bespoke decision-aid

Bounded rationality modeling

International audienc

A meta-analysis of maize and wheat yields in low-input vs. conventional and organic systems

Organic and low-input systems are proposed as ways to reduce the environmental impacts of agriculture. Previous studies have shown that yields of organic systems can be ∼19 to 25% lower than conventional systems. An intermediary, low-input system could be less damaging for the environment than conventional systems, while reducing yield losses in comparison with organic systems. In this study, we performed a meta-analysis to compare low-input systems to conventional and organic systems. Our analysis is based on data of cropping system experiments conducted in Europe and North America, and focuses on two important crops, maize (Zea mays L.) and soft winter wheat (Triticum aestivum L.). Pesticide use was greatly reduced for low-input systems as compared with conventional for the two crops (50% for maize, 70% for wheat on average). Mean mineral N use was also reduced by 36% for maize and 28% for wheat in low-input relative to conventional. Maize yields in low-input systems were not different from those in conventional systems, and were higher than yields in organic systems (yield ratio of low-input vs. organic = 1.24). Wheat yields in low-input systems were lower than yields in conventional systems (yield ratio of low-input vs. conventional = 0.88), but were substantially higher than yields in organic systems (yield ratio of low input vs. organic = 1.43). This is one of the first meta-analyses to assess performance in terms of pesticide use intensity, and yields, with clear evidence emerging that low-input systems can markedly reduce pesticide application, without strongly reducing crop yields, relative to conventional systems

Refined nash-equilibria as decision-aid tools ?

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : DO 2510 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Two classes of bacterial IMPDHs according to their quaternary structures and catalytic properties.

Inosine-5'-monophosphate dehydrogenase (IMPDH) occupies a key position in purine nucleotide metabolism. In this study, we have performed the biochemical and physico-chemical characterization of eight bacterial IMPDHs, among which six were totally unexplored. This study led to a classification of bacterial IMPDHs according to the regulation of their catalytic properties and their quaternary structures. Class I IMPDHs are cooperative enzymes for IMP, which are activated by MgATP and are octameric in all tested conditions. On the other hand, class II IMPDHs behave as Michaelis-Menten enzymes for both substrates and are tetramers in their apo state or in the presence of IMP, which are shifted to octamers in the presence of NAD or MgATP. Our work provides new insights into the IMPDH functional regulation and a model for the quaternary structure modulation is proposed