Schlauschleimer in Reichsautobahnen: Slime mould imitates motorway network in Germany

Purpose: The purpose of this paper is to develop experimental laboratory biological techniques for approximation of principle transport networks, optimizing transport links, and developing optimal solutions to current transport problems. It also aims to study how slime mould of Physarum polycephalum approximate autobahn networks in Germany. Design/methodology/approach: The paper considers the 21 most populous urban areas in Germany. It represents these areas with source of nutrients placed in the positions of slime mould growing substrate corresponding to the areas. At the beginning of each experiment slime mould is inoculated in the Berlin area. Slime mould exhibits foraging behavior and spans sources of nutrients (which represent urban areas) with a network of protoplasmic tubes (which approximate vehicular transport networks). The study analyzes structure of transport networks developed by slime mould and compares it with families of known proximity graphs. It also imitates slime-mould response to simulated disaster by placing sources of chemo-repellents in the positions of nuclear power plants. Findings: It is found that the plasmodium of Physarum polycephalum develops a minimal approximation of a transport network spanning urban areas. Physarum-developed network matches autobahn network very well. The high degree of similarity is preserved even when we place high-demand constraints on repeatability of links in the experiments. Physarum approximates almost all major transport links. In response to a sudden disaster, gradually spreading from its epicenter, the Physarum transport networks react by abandoning transport links affected by disaster zone, enhancement of those unaffected directly by the disaster, massive sprouting from the epicenter, and increase of scouting activity in the regions distant to the epicenter of the disaster. Originality/value: Experimental methods and computer analysis techniques presented in the paper lay a foundation of novel biological laboratory approaches to imitation and prognostication of socio-economical developments. © Emerald Group Publishing Limited

Uncertainty representation of grey numbers and grey sets

In the literature there is a presumption that a grey set and an interval-valued fuzzy set are equivalent. This presumption ignores the existence of discrete components in a grey number. In this paper new measurements of uncertainties of grey numbers and grey sets, consisting of both absolute and relative uncertainties, are defined to give a comprehensive representation of uncertainties in a grey number and a grey set. Some simple examples are provided to illustrate that the proposed uncertainty measurement can give an effective representation of both absolute and relative uncertainties in a grey number and a grey set. The relationships between grey sets and interval-valued fuzzy sets are also analysed from the point of view of the proposed uncertainty representation. The analysis demonstrates that grey sets and intervalvalued fuzzy sets provide different but overlapping models for uncertainty representation in sets

A Novel Synthetic Index of Two Counts and Mathematical Model for Researcher Evaluation

The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.Purpose – The purpose of this paper is to present a novel synthetic index of two counts and mathematical model for researcher evaluation. Design/methodology/approach –A synthetic index L for researcher evaluation considering both the total number of other citations (C) and non-academic impact (I), and a synthetic evaluation model is proposed in this paper. C and I are verified impact indexes. According to investigation by Delphi method, researchers are divided into five different classes of “below average”, “average”, “good”, “excellent” and “stellar”. The threshold values for counts C of grey class “stellar” are determined by deep investigation. The possibility functions of the two counts C and I on four grey classes of “below average”, “average”, “good”, and “excellent” are built. Findings –The novel synthetic index of two counts and mathematical model for researcher evaluation providing a better way to conduct researcher assessment. Practical implications –The synthetic index L presented in this paper can be used to evaluate a researcher. It’s more reasonable than the current research assessment indexes such as the number of publications and the numbers of so called high quality journal publications, and the amount of granted funds, etc. The synthetic index L reflect the actual value created by a researcher. No artificial manoeuvre can change them significantly. Originality/value –A synthetic index L for researcher evaluation considering both the total number of other citations (C) and non-academic impact (I), and a synthetic evaluation model is proposed in this paper

Managing physical inventory and return policies for omnichannel retailing

As the retail industry increasingly adopts an omnichannel strategy amidst the growth of e-commerce, this study explores the interplay between inventory and return policies in such a setting. Specifically, we focus on “return losses,” defined as the losses incurred by retailers due to customer product returns. We target how these return losses impact retailers’ profits and physical inventories. While previous research has mainly concentrated on cross-channel returns, little attention has been paid to how omnichannel return policies affect store inventory and profit. We posit that profit-maximizing retailers allow consumers to select their purchase channels based on utility but require returns to follow specific policies. In this paper, we model four return policies based on the channel of return: original purchasing channel return, offline return, online return, and cross-channel return. We use a newsvendor model to construct an optimal profit function that accounts for the additional profit from offline return, uncertainty demand, and inventory cost. Our analysis identifies the conditions under which certain return policies are beneficial or detrimental to omnichannel retailers. We discover that the retailer's product pricing, return losses, and consumer return hassle costs are the main factors influencing the best return policy and inventory policy decisions. Moreover, whether to increase or decrease store inventory and the relationship between physical inventory and return loss depend on the return policy, price, and return hassle cost. Numerical simulations support our findings, which offer practical guidance for omnichannel retailers aiming to optimize their inventory and return policies

Relation between China’s gasoline prices and international crude oil prices

China’s gasoline prices are still regulated by government although China's refined oil pricing mechanism has been reformed for many times. In this paper, proximity and similarity between China’s gasoline prices and Brent crude oil prices are calculated in the different stages with China’s refined oil pricing mechanism reforming, by using daily data and grey relational analysis method. The results show that there have undergone great changes of the similarity and proximity between China’s gasoline prices and international crude oil prices