Framework to Manage Customer Enquiries for SMEs

For most Smaller Manufacturing Enterprises (SMEs), how to manage customer enquiries at the customer enquiry stage is of great importance to maintain the competitive advantage and secure future customer orders. A lack of co-ordination between marketing/sales and production at this stage often leads to confirmed orders being delivered later than promised and/or being produced at a loss. In the paper, the problems and the solutions for managing customer enquiries faced by many SMEs are addressed. A general process for dealing with customer enquiries at the customer enquiry stage and a corresponding DSS approach are presented in detailed. The SMEs would benefit from the proposed DSS in which the considerations of current material and production capacity are given to the customer enquiry management process.Singapore-MIT Alliance (SMA

DSS Model for Profit Maximization at Customer Enquiry Evaluation Stage

This paper presents an optimal method and a heuristic approach which aims at maximizing the profit when responding to a set of customer enquiries under limited capacity. The model takes into consideration the quantity of available-to-promise (ATP) which measures the capability to fill customer orders, along with enquiry quantity and product price. The optimal method and the heuristic approach are tested using ATP, product price and enquiry quantity each at their different levels. From the example conducted, it is found that (1) the optimal model can help to make appropriate decision for selecting a subset of enquiries, and (2) the heuristic approach can produce a result within 5% from the optimum achieved by optimal method for most parameter settings.Singapore-MIT Alliance (SMA

Fulfillment of Rush Customer Orders under Limited Capacity

Customer demand fulfillment is the business process within a company that determines how the customer demand is fulfilled. A rush order is the last minute customer order after the production plan of a company has been concluded. For these rush orders, appropriate and reasonable response is imperative as it could put strain on customer relationship and services. A good and positive response could help the company to build and retain its market share in today’s highly competitive markets. A model aims at decreasing the product inventory cost is proposed in this paper. In this model, the prioritized fulfillment sequence of rush customer demands can be searched in terms of the product inventory cost. The paper focuses on two main issues: the available-to-promise (ATP) based fulfillment ability and the prioritized fulfillment of customer demands. For ATP based fulfillment, a dynamic bill-of-material (BOM) is proposed to handle the complicated issues of BOM, BOM explosion and production capacity. By means of dynamic BOM, material availability as well as production capacity can be taken into consideration simultaneously and efficiently. Two methods, mathematical optimization and heuristic algorithm, are constructed and elaborated on in the second issue. The proposed model allows companies to prioritize customer rush orders in terms of product inventory cost.Singapore-MIT Alliance (SMA

Compatibility Issues With Irregular Current Injection Islanding Detection Methods in Multi-DG Units Equipped With Grid-Connected Transformers

Compatibility issues with irregular current injection islanding detection methods are actually the problem that some irregular currents at the same frequency injected into the same line may cancel each other out and then the islanding detection may be impaired, which have been discussed under direct couple conditions (i.e., conditions without grid-connected transformers) in the literature. This article analyzes the issues under the opposite conditions where distributed generation (DG) units are equipped with grid-connected transformers, and is aimed at finding a solution. The analysis derives the setting formulas of key parameters for both three-phase and single-phase DG units, and shows that considering fault tolerance and practicability, only specific frequencies can be used for irregular currents. The usable frequencies are different under different cases. These conclusions are different from those based on direct couple conditions. By summarizing the conclusions based on conditions with grid-connected transformers achieved in this article and those based on direct couple conditions in the literature, a complete solution to compatibility issues is obtained. The conclusions in this article have been verified by the experiments and simulations at the end of this article

The role of Hall diffusion in the magnetically threaded thin accretion discs

We study role of the Hall diffusion in the magnetic star-disc interaction. In a simplified steady state configuration, the total torque is calculated in terms of the fastness parameter and a new term because of the Hall diffusion. We show the total torque reduces as the Hall term becomes more significant. Also, the critical fastness parameter (at which the total torque is zero) reduces because of the Hall diffusion.Comment: Accepted for publication in Astrophysics and Space Scienc

Quantum Efficiency of Charge Qubit Measurements Using a Single Electron Transistor

The quantum efficiency, which characterizes the quality of information gain against information loss, is an important figure of merit for any realistic quantum detectors in the gradual process of collapsing the state being measured. In this work we consider the problem of solid-state charge qubit measurements with a single-electron-transistor (SET). We analyze two models: one corresponds to a strong response SET, and the other is a tunable one in response strength. We find that the response strength would essentially bound the quantum efficiency, making the detector non-quantum-limited. Quantum limited measurements, however, can be achieved in the limits of strong response and asymmetric tunneling. The present study is also associated with appropriate justifications for the measurement and backaction-dephasing rates, which were usually evaluated in controversial methods.Comment: 10 pages, 2 figure

Interstellar MHD Turbulence and Star Formation

This chapter reviews the nature of turbulence in the Galactic interstellar medium (ISM) and its connections to the star formation (SF) process. The ISM is turbulent, magnetized, self-gravitating, and is subject to heating and cooling processes that control its thermodynamic behavior. The turbulence in the warm and hot ionized components of the ISM appears to be trans- or subsonic, and thus to behave nearly incompressibly. However, the neutral warm and cold components are highly compressible, as a consequence of both thermal instability in the atomic gas and of moderately-to-strongly supersonic motions in the roughly isothermal cold atomic and molecular components. Within this context, we discuss: i) the production and statistical distribution of turbulent density fluctuations in both isothermal and polytropic media; ii) the nature of the clumps produced by thermal instability, noting that, contrary to classical ideas, they in general accrete mass from their environment; iii) the density-magnetic field correlation (or lack thereof) in turbulent density fluctuations, as a consequence of the superposition of the different wave modes in the turbulent flow; iv) the evolution of the mass-to-magnetic flux ratio (MFR) in density fluctuations as they are built up by dynamic compressions; v) the formation of cold, dense clouds aided by thermal instability; vi) the expectation that star-forming molecular clouds are likely to be undergoing global gravitational contraction, rather than being near equilibrium, and vii) the regulation of the star formation rate (SFR) in such gravitationally contracting clouds by stellar feedback which, rather than keeping the clouds from collapsing, evaporates and diperses them while they collapse.Comment: 43 pages. Invited chapter for the book "Magnetic Fields in Diffuse Media", edited by Elisabete de Gouveia dal Pino and Alex Lazarian. Revised as per referee's recommendation

Integrated analyses of single-cell atlases reveal age, gender, and smoking status associations with cell type-specific expression of mediators of SARS-CoV-2 viral entry and highlights inflammatory programs in putative target cells

The COVID-19 pandemic, caused by the novel coronavirus SARS-CoV-2, creates an urgent need for identifying molecular mechanisms that mediate viral entry, propagation, and tissue pathology. Cell membrane bound angiotensin-converting enzyme 2 (ACE2) and associated proteases, transmembrane protease serine 2 (TMPRSS2) and Cathepsin L (CTSL), were previously identified as mediators of SARS-CoV2 cellular entry. Here, we assess the cell type-specific RNA expression of ACE2, TMPRSS2, and CTSL through an integrated analysis of 107 single-cell and single-nucleus RNA-Seq studies, including 22 lung and airways datasets (16 unpublished), and 85 datasets from other diverse organs. Joint expression of ACE2 and the accessory proteases identifies specific subsets of respiratory epithelial cells as putative targets of viral infection in the nasal passages, airways, and alveoli. Cells that co-express ACE2 and proteases are also identified in cells from other organs, some of which have been associated with COVID-19 transmission or pathology, including gut enterocytes, corneal epithelial cells, cardiomyocytes, heart pericytes, olfactory sustentacular cells, and renal epithelial cells. Performing the first meta-analyses of scRNA-seq studies, we analyzed 1,176,683 cells from 282 nasal, airway, and lung parenchyma samples from 164 donors spanning fetal, childhood, adult, and elderly age groups, associate increased levels of ACE2, TMPRSS2, and CTSL in specific cell types with increasing age, male gender, and smoking, all of which are epidemiologically linked to COVID-19 susceptibility and outcomes. Notably, there was a particularly low expression of ACE2 in the few young pediatric samples in the analysis. Further analysis reveals a gene expression program shared by ACE2(+)TMPRSS2(+) cells in nasal, lung and gut tissues, including genes that may mediate viral entry, subtend key immune functions, and mediate epithelial-macrophage cross-talk. Amongst these are IL6, its receptor and co-receptor, IL1R, TNF response pathways, and complement genes. Cell type specificity in the lung and airways and smoking effects were conserved in mice. Our analyses suggest that differences in the cell type-specific expression of mediators of SARS-CoV-2 viral entry may be responsible for aspects of COVID-19 epidemiology and clinical course, and point to putative molecular pathways involved in disease susceptibility and pathogenesis

What is the Oxygen Isotope Composition of Venus? The Scientific Case for Sample Return from Earth’s “Sister” Planet

Venus is Earth’s closest planetary neighbour and both bodies are of similar size and mass. As a consequence, Venus is often described as Earth’s sister planet. But the two worlds have followed very different evolutionary paths, with Earth having benign surface conditions, whereas Venus has a surface temperature of 464 °C and a surface pressure of 92 bar. These inhospitable surface conditions may partially explain why there has been such a dearth of space missions to Venus in recent years.The oxygen isotope composition of Venus is currently unknown. However, this single measurement (Δ17O) would have first order implications for our understanding of how large terrestrial planets are built. Recent isotopic studies indicate that the Solar System is bimodal in composition, divided into a carbonaceous chondrite (CC) group and a non-carbonaceous (NC) group. The CC group probably originated in the outer Solar System and the NC group in the inner Solar System. Venus comprises 41% by mass of the inner Solar System compared to 50% for Earth and only 5% for Mars. Models for building large terrestrial planets, such as Earth and Venus, would be significantly improved by a determination of the Δ17O composition of a returned sample from Venus. This measurement would help constrain the extent of early inner Solar System isotopic homogenisation and help to identify whether the feeding zones of the terrestrial planets were narrow or wide.Determining the Δ17O composition of Venus would also have significant implications for our understanding of how the Moon formed. Recent lunar formation models invoke a high energy impact between the proto-Earth and an inner Solar System-derived impactor body, Theia. The close isotopic similarity between the Earth and Moon is explained by these models as being a consequence of high-temperature, post-impact mixing. However, if Earth and Venus proved to be isotopic clones with respect to Δ17O, this would favour the classic, lower energy, giant impact scenario.We review the surface geology of Venus with the aim of identifying potential terrains that could be targeted by a robotic sample return mission. While the potentially ancient tessera terrains would be of great scientific interest, the need to minimise the influence of venusian weathering favours the sampling of young basaltic plains. In terms of a nominal sample mass, 10 g would be sufficient to undertake a full range of geochemical, isotopic and dating studies. However, it is important that additional material is collected as a legacy sample. As a consequence, a returned sample mass of at least 100 g should be recovered.Two scenarios for robotic sample return missions from Venus are presented, based on previous mission proposals. The most cost effective approach involves a “Grab and Go” strategy, either using a lander and separate orbiter, or possibly just a stand-alone lander. Sample return could also be achieved as part of a more ambitious, extended mission to study the venusian atmosphere. In both scenarios it is critical to obtain a surface atmospheric sample to define the extent of atmosphere-lithosphere oxygen isotopic disequilibrium. Surface sampling would be carried out by multiple techniques (drill, scoop, “vacuum-cleaner” device) to ensure success. Surface operations would take no longer than one hour.Analysis of returned samples would provide a firm basis for assessing similarities and differences between the evolution of Venus, Earth, Mars and smaller bodies such as Vesta. The Solar System provides an important case study in how two almost identical bodies, Earth and Venus, could have had such a divergent evolution. Finally, Venus, with its runaway greenhouse atmosphere, may provide data relevant to the understanding of similar less extreme processes on Earth. Venus is Earth’s planetary twin and deserves to be better studied and understood. In a wider context, analysis of returned samples from Venus would provide data relevant to the study of exoplanetary systems