Determining profit-optimizing return policies – a two-step approach on data from taobao.com

Selecting an optimal return policy requires taking into account two effects: the potential positive effect on sales and the potential negative effect of higher costs. We propose a two-step model, in which we first utilize a robust regression to explain purchase behavior, and then apply a zero-inflated negative binominal regression to model the return behavior. We apply this model to data from the most important online platform in China and obtain three main findings. First, the adoption of return policies results in increased sales, while reputation works as a moderator in this process. Second, good reputation and traditional customer friendly return policies (like the Seven-Day Return policy) can significantly increase the number of returns, while more guarantee credibility (enhanced by Guarantee Money) is related to fewer returns. Taken together, both the Seven-Day Return policy (profit increase of +0.29 %) and Guarantee Money (profit increase of +0.016 % per Yuan guarantee) ultimately increase firms’ profit.     

Residual tumor after laser ablation of human non-small-cell lung cancer demonstrated by ex vivo staining: correlation with invasive temperature measurements

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Histology is the gold standard for confirming thermally induced necrosis. Generally, however, no specimen is obtained from thermal ablation therapy for pathological examination. The aim of this study was to provide evidence for the relationship between temperatures reached and resulting tissue coagulation during laser ablation in a near-physiological ex vivo lung tumor model by combining viability staining and direct temperature measurement.     

Etablierung einer nationalen Rohstoffbuchhaltung und dafür notwendige Informationen und Informationsgüte

The influence of anthropogenic processes on global material flow systems increasingly dominates the influence of natural processes. In this context, the provision of detailed knowledge on material flow systems is relevant for decision makers in resource policy. This information can be provided in the form of one-year material balances or, if repeated over a period of consecutive years, in the form of national resource budgets. In national resource budgets, all relevant flows of a material through a national economy are balanced and displayed in neatly arranged diagrams. By updating these material balances over a series of years, the development of material stocks can be estimated. Upcoming challenges both regarding supply and disposal of materials can be identified. Comprehensive balances are useful for decision makers in resource policy and, moreover, as an information basis for future exploitation of anthropogenic resources. However, both availability of data and possibilities for assessing the reliability of data are very limited. In this work, a methodology for investigating and evaluating the information basis of national resource budgets is presented. The methodology includes procedures for systematic characterization of resource budget data and formal procedures for evaluating their reliability. From a scientific perspective, the methodology contributes to understanding material flow systems better. It also enables implementing procedures towards national resource budgets in an administrative context.     

Anteil erneuerbarer Energien und klimarelevante CO2-Emissionen aus der thermischen Verwertung von Abfällen in Österreich

Since combustible wastes usually consist of biogenic (e.g. paper, wood, food waste) and fossil organic matter (plastics), their thermal recovery results in climate neutral and climate relevant CO₂ emissions. Moreover, the fraction of biogenic materials in the waste feed is relevant for the amount of renewable energy produced. The latter has to be reported and might be subsidized according to national laws (e.g. based on European directive 2009/28/EG). The present study represents the first comprehensive evaluation of the share of biogenic and fossil materials in the waste feed of waste-to-energy (WTE) plants on a national basis. The Balance Method, which is patented on a European level by TU Wien, was applied to 10 out of 13 Austrian WTE plants (around 2.3 Mio tons of waste corresponding to around 88 % of the overall waste feed in Austrian WTE plants). The method is based on the mathematical reconciliation of the material properties (e.g. mean chemical composition of biogenic and fossil materials) and routinely recorded operating data of WTE plants (e.g. flue gas volume, CO₂ and O₂-content in the dry flue gas, steam production). The results demonstrate large variations for the share of energy from biogenic sources in the different WTE plants, ranging from 35.7 ± 2.4 % to 61.2 ± 2.7 % (based on annual averages). Additionally, for several WTE plants large temporal variations can be observed based on monthly mean values. Thus, a plant-specific and continuous evaluation of the waste composition in WTE plants (which the Balance Method allows to do at reasonable efforts) can be recommended for a reliable reporting of the renewable share of energy or fossil CO₂ emissions from waste incineration. The energy input which stems from fossil and biogenic sources can be estimated to 11,450 ± 120 TJ and 10,730 ± 110 TJ, respectively for the year 2014 (for the 10 WTE plants). In total 1060 ± 24 kt fossil CO₂ emissions from the thermal recovery of waste in Austria’s WTE plants in 2014 could be determined (estimation for all 13 WTE plants).     

Inelastic Neutron Scattering and Density Functional Theory–Molecular Dynamics Study of Si Dynamics in Ti3SiC2

Observed differences between measured and calculated elastic constants for Ti₃SiC₂ are investigated using Density Functional Theory and Inelastic Neutron Scattering. The agreement between the calculated lattice dynamics and the dynamics measured by inelastic neutron scattering is considered good except at energies below ~20 meV where discrepancies suggest anharmonic potentials. This suggestion is confirmed by Density Functional Theory—Molecular Dynamics simulation which shows multiple site occupancy of the Si atoms within the basal plane at finite temperature and produces a calculated inelastic spectrum in better agreement with the measured spectrum in the low‐energy region. The highly anharmonic potential energy surface of the Si atoms offers an explanation for the failure of elastic constants, calculated based on the harmonic approximation, to agree with initial experimental measurements.     

Noise covariance matrices in state‐space models: A survey and comparison of estimation methods—Part I

This paper deals with the estimation of the noise covariance matrices of systems described by state‐space models. Stress is laid on the systematic survey and classification of both the recursive and batch processing methods proposed in the literature with a special focus on the correlation methods. Besides the correlation methods, representatives of other groups are introduced also with respect to their basic idea, estimate properties, assumptions and possible extensions, and user‐defined parameters. Common and dual properties of the methods are highlighted, and a simulation comparison using exemplary MATLAB implementations of the methods is provided.