Towards Predictive Energy Management in Information Systems: A Research Proposal

The progressive energy transition, driven by the growing number of renewable energies, the increasing social importance of sustainable actions, as well as new technologies, causes major challenges for enterprises and power supply companies (PSCs). While the electricity price fluctuations will continue to increase in the future, the installation of smart meters and smart meter gateways is aimed to ensure grid stability. They provide the basis for communication between companies and PSCs. In order to make companies energy consumption predictable even before the energy is needed, an automated data exchange between an energy management system (EnMS) and enterprise resource planning (ERP) system is essential. Therefore, we address this problem by following five research steps to develop a prototype for predictive energy management in information systems

Openness of Digital Twins in Logistics – A Review

Openness is becoming increasingly important in scientific research and practice. It describes the phenomenon of sharing information with other internal or external stakeholders by using different technologies, e.g., cloud computing, distributed ledger, or digital twins. Hence, many researchers investigate and evaluate the openness of platforms. Alongside these platforms, digital twins are gaining influence in industrial processes. A digital twin is a virtual representation of a physical entity connected through a bi-directional data linkage. Its primary purpose is to visualize, analyze, and optimize production and logistics systems. Nevertheless, research shows a lack of knowledge in the domain of the openness of digital twins and that the topic has not been addressed adequately. To approach this research gap, this paper provides a review of literature-based work on digital twins focusing on logistical contexts. It aims to answer the question of how open digital twins are, depending on their use case, purpose, and status as digital twin or digital shadow. Through a comprehensive research approach, this paper provides researchers and practitioners with meaningful insights into the openness of digital twins

Dynamic Stochastic Inventory Management in E-Grocery Retailing: The Value of Probabilistic Information

Inventory management optimisation in a multi-period setting with dependent demand periods requires the determination of replenishment order quantities in a dynamic stochastic environment. Retailers are faced with uncertainty in demand and supply for each demand period. In grocery retailing, perishable goods without best-before-dates further amplify the degree of uncertainty due to stochastic spoilage. Assuming a lead time of multiple days, the inventory at the beginning of each demand period is determined jointly by the realisations of these stochastic variables. While existing contributions in the literature focus on the role of single components only, we propose to integrate all of them into a joint framework, explicitly modelling demand, supply shortages, and spoilage using suitable probability distributions learned from historic data. As the resulting optimisation problem is analytically intractable in general, we use a stochastic lookahead policy incorporating Monte Carlo techniques to fully propagate the associated uncertainties in order to derive replenishment order quantities. We develop a general inventory management framework and analyse the benefit of modelling each source of uncertainty with an appropriate probability distribution. Additionally, we conduct a sensitivity analysis with respect to location and dispersion of these distributions. We illustrate the practical feasibility of our framework using a case study on data from a European e-grocery retailer. Our findings illustrate the importance of properly modelling stochastic variables using suitable probability distributions for a cost-effective inventory management process

GWAS of adventitious root formation in roses identifies a putative phosphoinositide phosphatase (SAC9) for marker-assisted selection

Rose propagation by cuttings is limited by substantial genotypic differences in adventitious root formation. To identify possible genetic factors causing these differences and to develop a marker for marker-assisted selection for high rooting ability, we phenotyped 95 cut and 95 garden rose genotypes in a hydroponic rooting system over 6 weeks. Data on rooting percentage after 3 to 6 weeks, root number, and root fresh mass were highly variable among genotypes and used in association mappings performed on genotypic information from the WagRhSNP 68 K Axiom SNP array for roses. GWAS analyses revealed only one significantly associated SNP for rooting percentage after 3 weeks. Nevertheless, prominent genomic regions/peaks were observed and further analysed for rooting percentage after 6 weeks, root number and root fresh mass. Some of the SNPs in these peak regions were associated with large effects on adventitious root formation traits. Very prominent were ten SNPs, which were all located in a putative phosphoinositide phosphatase SAC9 on chromosome 2 and showed very high effects on rooting percentage after 6 weeks of more than 40% difference between nulliplex and quadruplex genotypes. SAC9 was reported to be involved in the regulation of endocytosis and in combination with other members of the SAC gene family to regulate the translocation of auxin-efflux PIN proteins via the dephosphorylation of phosphoinositides. For one SNP within SAC9, a KASP marker was successfully derived and used to select genotypes with a homozygous allele configuration. Phenotyping these homozygous genotypes for adventitious root formation verified the SNP allele dosage effect on rooting. Hence, the presented KASP derived from a SNP located in SAC9 can be used for marker-assisted selection in breeding programs for high rooting ability in the future

Simulation of impaction filtration of aerosol droplets in porous media

We report on the development of a method to simulate from first principles the particle filtration efficiency of filters that are composed of structured porous media. We assume that the ratio of particle density to the fluid density is high. We concentrate on the motion of the particles in a laminar flow and quantify the role of inertial effects on the filtration of an ensemble of particles. We adopt the Euler-Lagrange approach, distinguishing a flow field in which the motion of a large number of discrete particles is simulated. We associate filtration with the deterministic collision of inertial particles with solid elements of the structured porous medium. To underpin the physical `consistency' of deterministic particle filtration, we investigate to what extent the particle tracking algorithm ensures that mass-less test-particles will not be captured by the structured porous filter at all. This element of the algorithm is essential in order to distinguish physical filtration by inertial effects from unwanted numerical filtration, due to the finite spatial resolution of the gas flow. We consider filtration of particles whose motion is governed by Stokes drag and determine the filtration efficiency in a range of Stokes relaxation times. An exponential decay of the number of particles with time is observed

Crystal structures reveal the molecular basis of ion translocation in sodium/proton antiporters

To fully understand the transport mechanism of Na+/H+ exchangers, it is necessary to clearly establish the global rearrangements required to facilitate ion translocation. Currently, two different transport models have been proposed. Some reports have suggested that structural isomerization is achieved through large elevator-like rearrangements similar to those seen in the structurally unrelated sodium-coupled glutamate-transporter homolog GltPh. Others have proposed that only small domain movements are required for ion exchange, and a conventional rocking-bundle model has been proposed instead. Here, to resolve these differences, we report atomic-resolution structures of the same Na+/H+ antiporter (NapA from Thermus thermophilus) in both outward- and inward-facing conformations. These data combined with cross-linking, molecular dynamics simulations and isothermal calorimetry suggest that Na+/H+ antiporters provide alternating access to the ion-binding site by using elevator-like structural transitions

Interplay of Andreev reflection and Coulomb blockade in hybrid superconducting single electron transistors

We study the interplay between Coulomb blockade and superconductivity in a tunable superconductor-superconductor-normal metal single-electron transistor. The device is realized by connecting the superconducting island via an oxide barrier to the normal metal lead and with a break junction to the superconducting lead. The latter enables Cooper pair transport and (multiple) Andreev reflection. We show that those processes are relevant also far above the superconducting gap and that signatures of Coulomb blockade may reoccur at high bias while they are absent for small bias in the strong-coupling regime. Our experimental findings agree with simulations using a master equation approach in combination with the full counting statistics of multiple Andreev reflection.Comment: Manuscript only, supplement available upon reques

Practical Requirements for Digital Twins in Production and Logistics

Companies are under tremendous pressure to analyze and optimize their productional and logistical networks in today's global business world. Hence, practitioners and researchers show great interest in digital twins. A digital twin is a virtual construct that mirrors real-world objects and conceptual ideas while it processes, handles, distributes, and optimizes data streams. Its main purpose is to visualize, analyze, and optimize objects and systems, making a digital twin highly suitable to help companies gain an advantage over their competitors through a great degree of transparency over their production and logistics. Therefore, almost every company evaluates the usage of digital twins. Nevertheless, many companies struggle to instantiate digital twins since they lack fundamental knowledge about all necessary components of a digital twin and the individual requirements for the operation of the digital twin. This lack of knowledge hinders the broad implementation in practice. Research shows many descriptions of theoretical use cases and field studies but rarely describes digital twins in real operational settings. To address this research gap between theoretical concepts and practical challenges of the implementation of digital twins, this paper investigates the practical requirements of digital twins in real-life usage. Based on a thorough interview series with international manufacturing and logistics experts, we identify and analyze the requirements for data handling, data policy, and services of digital twins and cluster them according to the requirements engineering approach. Through a comprehensive overview of the different requirements, the paper delivers profound insights into the needs of companies from various fields and, therefore, gives practitioners a guideline on crucial aspects of implementing digital twins