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The inventory levels of pickup points play an important role for the same-day or next-day pickup and delivery services. The previous inventory optimisation research usually makes an assumption about demand distribution, does not use the real dataset or consider shipping strategies for this problem. In this study, we introduce a new strategy, mixture of anticipatory and emergency shipping, and propose forecasting-optimisation integrated approach to optimise multi-items' inventories in each pickup point based on big data analysis. We explore a real dataset including 23,808,261 records with 54 pickup points and 4018 items. We first cluster the dataset based on the distances between pickup points and the warehouse, then, implement the forecasting-optimisation integrated algorithms to select the more profitable strategy for each group. The result indicates that compared with the original algorithms, our proposed approach can effectively increase the profits, particularly, the novel algorithm, Long Short-Term Memory networks – Quantile Regression, performs better. Additionally, we find that the 100% anticipatory shipping is not necessarily superior to emergency shipment, when the pickup point is farther from the warehouse, the advantage of emergency shipment is more significant. However, the mixture of anticipatory and emergency shipping can contribute to higher profits for online retailers. [ABSTRACT FROM AUTHOR]

Vendor credit line ( VCL ) is a common instrument to fund retailers with capital constraints, wherein a supplier extends credit for a retailer's purchases and limits credit size for the sake of default risk. Our study investigates the operational and financial decisions in a supply chain consisting of a supplier and a capital-constrained retailer, wherein the supplier sets credit limits for the retailer's ordering, and then examines the financing choice between VCL and bank loan. We derive the equilibrium credit limits, order quantity and financing mode and conclude that, the credit limits linearly increase with the capital level, and both credit limits and capital level are decisive to the order quantity and financing mode. In the illustrating examples, we identify the decision regions contingent on critical fractiles under different demand distributions (e.g., normal, uniform and exponential) and find the financing choice hinging on the supplier's profit margin if the capital level stays low, otherwise VCL dominates. Finally, sensitivity analysis on key parameters is employed, suggesting that VCL is more preferable as the wholesale price increases or as the retail price and production cost decreases. [ABSTRACT FROM AUTHOR]

Background and purpose: This study aimed to investigate the clinical efficacy and safety of telitacicept in patients with generalized myasthenia gravis (gMG) who tested positive for acetylcholine receptor antibodies or muscle‐specific kinase antibodies and were receiving standard‐of‐care therapy. Methods: Patients meeting the eligibility criteria were randomly assigned to receive telitacicept subcutaneously once a week for 24 weeks in addition to standard‐of‐care treatment. The primary efficacy endpoint was the mean change in the quantitative myasthenia gravis (QMG) score from baseline to week 24. Secondary efficacy endpoints included mean change in QMG score from baseline to week 12 and gMG clinical absolute score from baseline to week 24. Additionally, safety, tolerability and pharmacodynamics were assessed. Results: Twenty‐nine of the 41 patients screened were randomly selected and enrolled. The mean (± standard deviation [SD]) reduction in QMG score from baseline to week 24 was 7.7 (± 5.34) and 9.6 (± 4.29) in the 160 mg and 240 mg groups, respectively. At week 12, mean reductions in QMG scores for these two groups were 5.8 (± 5.85) and 9.5 (± 5.03), respectively, indicating rapid clinical improvement. Safety analysis revealed no adverse events leading to discontinuation or mortalities. All patients showed consistent reductions in serum immunoglobulin (Ig) A, IgG and IgM levels throughout the study. Conclusion: Telitacicept demonstrated safety, good tolerability and reduced clinical severity throughout the study period. Further validation of the clinical efficacy of telitacicept in gMG will be conducted in an upcoming phase 3 clinical trial. [ABSTRACT FROM AUTHOR]

With data-driven optimization, this study investigates the sellers' inventory replenishment and financial decisions, and lenders' interest rate decisions in online retailing platforms. Moreover, we focus on the annual large-scale promotion, which requires massive capital in a short period. While scholars studying the data-driven inventory replenishment problem hardly consider capital-constrained sellers, these problems are important because the seller's capital level can significantly influence the order quantity and generate different effects on inventory management. Hence, we propose two novel data-driven game-theoretic approaches (including separated and integrated methods) using machine learning and deep learning methods to optimize inventory replenishment and financial decisions for the sellers who obtain financial support from the online platform. Moreover, we propose a data-driven game-theoretic model for the online platform to optimize their interest rate considering the market potential. We explore the real retailing transaction data containing 199,390 weekly sales records. We find that the seller and lender can benefit when the seller chooses integrated machine learning and quantile regression method. However, we find that only a low capital level can motivate the seller to choose to borrow from the lender. Interestingly, our results also suggest that the lender has the motivation to build a data-driven system that helps sellers optimize inventory decisions. Our work identifies the optimal interest rate and inventory decision under the data-driven method. We propose data-driven decision support tools by evaluating the values of both the lender's and the seller's profit and provide new management insights on joint inventory and financing decisions. [ABSTRACT FROM AUTHOR]

The nickel carbon conductive HTV silicone rubber was prepared by additional silicone rubber as the base rubber, nickel carbon particles as conductive fillers, with coupling agent, thickening agent, and hydrogen containing silicone oil. The optimal formula for silicone rubber was explored and its performance was tested. The results showed that the optimal formula was that 100 parts of additional cured silicone rubber, 150 parts of nickel carbon particle A, 1. 5 parts of TTS coupling agent, 1 part of tackifier and 3 parts of hydrogen containing silicone oil. The silicone rubber by this formula has the surface resistance of 29. 47 mΩ, the adhesion of 23. 66 N, the density of 1. 93 g/ cm3, Shore A hardness of 65, the tensile strength of 1. 21 MPa, the elongation at break of 119%, and the resistance remains stable after 1,000 hours of double "85" aging test, which can meet the basic requirements for the conductive silicone rubber. [ABSTRACT FROM AUTHOR]

This paper explores the optimal joint decision of product information disclosure and ordering in a blockchain-enabled luxury supply chain. Using analytical models, we investigate the optimal joint decision of information disclosure and ordering under three scenarios (i.e., wholesale contracts only, revenue-sharing (RS) contracts only, and a hybrid of these two types of contracts). Furthermore, we extend our study to examine the impacts of the number of competing retailers and the retailers' fairness concerns on supply chain members' optimal decisions. Lastly, the theoretical results are checked and illustrated by numerical examples with sensitivity analysis. The main findings are as follows: (1) As the proportion of information-sensitive consumers in the market increases, the level of product information disclosure of supply chain members increases in varying degrees, while supply chain members' order quantities and profits first decrease and then increase in varying degrees. (2) When a RS contract is acceptable for all supply chain members, all members benefit from the cooperation between the manufacturer and retailers. (3) Although all supply chain members may benefit from an increase in the number of retailers, when the number of retailers is greater than a certain threshold, retailers would be caught in a "prisoner's dilemma" of product information disclosure due to consumer information overload. Moreover, to maximize business profits, manufacturers should sometimes strictly limit and control the number of their reseller partners, rather than blindly expand their markets. (4) Retailers may benefit from their own fairness concerns if and only if the level of fairness concerns is sufficiently low, otherwise such concerns would be harmful to all supply chain members. [ABSTRACT FROM AUTHOR]

Drones are increasingly used to deliver packages with high efficiency in several areas. We study a multi-warehouse drone delivery system, considering the allocation rule that all warehouses share the drones and the allocation rule that each warehouse owns its drones. Both plug-in charge and battery swap strategies are investigated for battery management. We examine the random and closest drone to warehouse assignment rules, and design a heuristic to improve the drone to warehouse assignment rule. A closed queueing network is built to estimate the maximum throughput capacity and a cost minimisation model is developed for cost analysis. We validate the analytical model by simulation and conduct numerical experiments to analyse the operating polices. The results show that the closest drone to warehouse assignment rule outperforms the random drone to warehouse assignment rule when the number of drones is not large, and our heuristic can improve the throughput capacity by about 13.31%. The battery swap strategy provides a better throughput capacity than the plug-in charge strategy in most cases, while it needs more investment. Moreover, the shared allocation rule gives a larger throughput capacity than the dedicated allocation rule, and it reduces the operating cost by about 30.70%. [ABSTRACT FROM AUTHOR]

This paper studies a three-dimensional automated storage and retrieval system that uses conveyors for depth transportation and a crane for both horizontal and vertical transportation. While previous studies put input and output points together at the system bottom, we consider separating and elevating them by proposing four I/O point policies: input and output points at two sides, input and output points elevated at one side, input and output points elevated at two sides, input and output points elevated at a midpoint. We build travel time models to analyse these policies and use simulation for validation. We theoretically find the optimal system structure and compare these I/O point policies, in terms of expected S/R machine travel time. The results show that the square-in-time structure is optimal in most cases and the mid-point elevation I/O point policy performs the best in terms of expected travel time. Moreover, we compare our I/O point policies with the lower mid-point policy. The results show that the mid-point elevation I/O point policy outperforms the I/O point at the lower mid-point by about 6.07 % in terms of expected travel time, while other I/O point policies are dominated by the I/O point at the lower mid-point. [ABSTRACT FROM AUTHOR]

Purpose: This study investigates the impacts of return channel type on the relationships between return service quality (RSQ) and customer loyalty (CL) in an omnichannel retailing environment. Design/methodology/approach: Data comes from Chinese customers having a return experience in omnichannel retailing that uses the channel type of both buy-online-return-in-store (BORIS) and buy-in-store-return-to-online warehouses (BSROW). The authors use the structural equation modeling to test the hypotheses and the bootstrapping method to test the mediation and moderation effect. Findings: For BORIS channel, satisfaction of customer returns (CRS) partially mediates the relationship between convenience and CL, and fully mediates that between CL and responsiveness, transparency and competence, respectively. For BSROW channel, CRS partially mediates the relationship between responsiveness and CL, and fully mediates that between CL and convenience, transparency and competence, respectively. The mediation effects indicate that omnichannel customers may feel more satisfied due to higher omnichannel fulfillment (responsiveness and convenience) and omnichannel trust (transparency and competence) provided by retailers. Return channel type moderates the relationship between RSQ-convenience and CL. The results show the different expectations between BORIS and BSROW customers in the return process. Research limitations/implications: This paper serves as a pioneering study to apply cognition-affect-behavior paradigm into the field of return management in omnichannel retailing. Practical implications: The findings suggest retailers develop their strategies on customer returns and post-sales service quality improvement in the omnichannel. Also, retailers should develop an integrated return system across channels to provide convenient service to BORIS customers and quick response to BSROW customers. Originality/value: Studying return service management in the omnichannel from customer's cognition appraisal, this study contributes to the literature of the reverse service management by bringing in the effect of omnichannel type to explore the relationship between RSQ and CL. [ABSTRACT FROM AUTHOR]

Genome‐scale metabolic models (GEMs) have been widely used to guide the computational design of microbial cell factories, and to date, seven GEMs have been reported for Bacillus subtilis, a model gram‐positive microorganism widely used in bioproduction of functional nutraceuticals and food ingredients. However, none of them are widely used because they often lead to erroneous predictions due to their low predictive power and lack of information on regulatory mechanisms. In this work, we constructed a new version of GEM for B. subtilis (iBsu1209), which contains 1209 genes, 1595 metabolites, and 1948 reactions. We applied machine learning to fill gaps, which formed a relatively complete metabolic network able to predict with high accuracy (89.3%) the growth of 1209 mutants under 12 different culture conditions. In addition, we developed a visualization and code‐free software, Model Tool, for multiconstraints model reconstruction and analysis. We used this software to construct etiBsu1209, a multiscale model that integrates enzymatic constraints, thermodynamic constraints, and transcriptional regulatory networks. Furthermore, we used etiBsu1209 to guide a metabolic engineering strategy (knocking out fabI and yfkN genes) for the overproduction of nutraceutical menaquinone‐7, and the titer increased to 153.94 mg/L, 2.2‐times that of the parental strain. To the best of our knowledge, etiBsu1209 is the first comprehensive multiscale model for B. subtilis and can serve as a solid basis for rational computational design of B. subtilis cell factories for bioproduction. [ABSTRACT FROM AUTHOR]

Retinol, the main active form of vitamin A, plays a role in maintaining vision, immune function, growth, and development. It also inhibits tumor growth and alleviates anemia. Here, we developed a Saccharomyces cerevisiae strain capable of high retinol production. Firstly, the de novo synthesis pathway of retinol was constructed in S. cerevisiae to realize the production of retinol. Second, through modular optimization of the metabolic network of retinol, the retinol titer was increased from 3.6 to 153.6 mg/L. Then, we used transporter engineering to regulate and promote the accumulation of the intracellular precursor retinal to improve retinol production. Subsequently, we screened and semi-rationally designed the key enzyme retinol dehydrogenase to further increase the retinol titer to 387.4 mg/L. Lastly, we performed two-phase extraction fermentation using olive oil to obtain a final shaking flask retinol titer of 1.2 g/L, the highest titer reported at the shake flask level. This study laid the foundation for the industrial production of retinol. [ABSTRACT FROM AUTHOR]

Three-dimensional compact automated storage/retrieval systems (AS/RS) have been extensively applied in warehouses, with advantages of full automation, time efficiency and high space utilisation. While previous studies that use lower mid-point input/output (I/O) dwell point policy consider single-command cycles (SC), this paper builds travel-time models of dual-command cycles (DC). The S/R crane also dwells in the lower mid-point of the rack when it is idle. We validate analytical models using simulation and use analytical models to optimise system dimensions. Numerical experiments are used to compare DC with SC. The results show that DC outperform SC in terms of cycle time of one command. [ABSTRACT FROM AUTHOR]

High-sugar diet causes health problems, many of which can be addressed with the use of sugar substitutes. Rubusoside and rebaudiosides are interesting molecules, considered the next generation of sugar substitutes due to their low-calorie, superior sweetness and organoleptic properties. However, their low abundance in nature makes the traditional plant extraction process neither economical nor environmental-friendly. Here we engineer baker's yeast Saccharomyces cerevisiae as a chassis for the de novo production of rubusoside and rebaudiosides. In this process, we identify multiple issues that limit the production, including rate-liming steps, product stress on cellular fitness and unbalanced metabolic networks. We carry out a systematic engineering strategy to solve these issues, which produces rubusoside and rebaudiosides at titers of 1368.6 mg/L and 132.7 mg/L, respectively. The rubusoside chassis strain here constructed paves the way towards a sustainable, large-scale fermentation-based manufacturing of diverse rebaudiosides. Rubusoside and rebaudiosides are considered the next generation of sugar substitutes. In this article, the authors report the engineering of Saccharomyces cerevisiae, remodelling the complex metabolic networks by a modular engineering approach, obtaining rubusoside and rebaudiosides at titers of around 1.4 g/L and 100 mg/L, respectively. [ABSTRACT FROM AUTHOR]

Colanic acid can promote the lifespan of humans by regulating mitochondrial homeostasis, and it has widespread applications in the field of health. However, colanic acid is produced at a low temperature (20 °C) with low titer. Using Escherichia coli K-12 MG1655, we constructed the SRP-4 strain with high colanic acid production at 30 °C by enhancing the precursor supply and relieving the regulation of transcription for colanic acid synthesis genes by the RCS system. After media optimization, the colanic acid titer increased by 579.9-fold and reached 12.2 g/L. Subsequently, we successfully purified the colanic acid hydrolase and reduced the molecular weight of colanic acid (106.854 kDa), thereby eliminating the inhibition of high-molecular-weight colanic acid on strain growth. Finally, after adding the colanic acid hydrolase (4000 U/L), the colanic acid with low molecular weight reached 24.99 g/L in 3-L bioreactor, the highest titer reported so far. This high-producing strain of colanic acid will promote the application of low-molecular-weight colanic acid in the field of health. [ABSTRACT FROM AUTHOR]

We study robotic mobile fulfilment systems for online retailers, where products are stored in movable shelves and robots transport shelves. While previous studies assume random assignment rule of workstations to robots, we propose an assignment rule based on handling speeds of workstations and design a neighbourhood search algorithm to find a near optimal assignment rule. We build semi-open queueing networks and use a two-phase approximate approach for performance estimation. We first replace workstation service processes by a composite service node and then solve the model by the matrix-geometric method. Simulations are used to validate the analytical models. Numerical experiments are conducted to compare random, handling-speeds-based, near optimal and optimal assignment rules, in terms of retrieval throughput time. The results show that the random assignment rule is not a good choice, the handling-speeds-based assignment rule significantly outperforms the random assignment rule when the workers have large handling time difference, and the neighbourhood search approach can provide an assignment rule that is very close to the optimal one, using a much shorter time. Moreover, we design the shelf blocks under the examined assignment rules, and find that the optimal width of shelf block decreases with the width to length ratio. [ABSTRACT FROM PUBLISHER]

Many distribution centers use expensive, conveyor-based sorting systems that require large buildings to house them. In areas with tight space, robotic sorting systems offer a new type of solution to sort parcels by destination. Such systems are highly flexible in throughput capacity and are now gradually being introduced, particularly in express companies. This paper studies robotic sorting system with two layouts. The first layout has two tiers: robots drive on the top tier and sort parcels by destination on spiral conveyors connected to roll containers at the lower tier. The second layout has a single tier with input and output points located at the perimeter, connected by robots. For each layout, we consider both the shortest path topology via dual-lane aisles and the detour path topology via single-lane aisles. We build closed queueing networks for performance estimation, design an iterative procedure to investigate robot congestion in the two-tier layout, and use a traffic flow function to estimate robot congestion in the single-tier layout. Random, closest, dedicated, and shortest-queue robot-to-loading-station assignment rules are examined. We validate analytical models by both simulation and a real case of Deppon Express and analyze the optimal system size and operating policies for throughput capacity and operating cost. The results show that the system throughput capacity is significantly affected by robot congestion in the single-tier layout with the detour path topology, but it is only slightly affected in the other systems. A square layout fits the shortest path and a rectangular layout fits the detour path. Both the random assignment rule and the shortest-queue assignment rule are superior for a large number of robots, whereas the dedicated assignment rule is superior for a small number of robots. We apply these insights at Deppon Express for different allocations in peak and off-peak hours. Our analysis shows that a robotic sorting system typically has lower overall annual cost than a traditional cross-belt sorting system when the required throughput capacity is not too large. [ABSTRACT FROM AUTHOR]

Double-deep multi-aisle automated storage/retrieval systems are increasingly applied for storing and retrieving unit loads, with advantages of increased space utilisation, reduced number of aisles and improved efficiency of storage rack (S/R) machines. In such systems, the retrieval process may consist of the rearrangement of blocking loads, based on the assumptions of uniformly distributed storage locations and random storage policy. We formulate analytical travel-time models of both single- and dual-command cycles under three rearrangement rules. We validate the analytical travel-time models by simulation and conduct numerical experiments to analyse the effect of the number of aisles an S/R machine serves, the fill-grade factor and the command cycles on the expected travel time of the S/R machine. The results show that the expected travel time of the S/R machine is increasing with the increase in the number of aisles an S/R machine serves and the increase in the fill-grade factor, and dual command cycle outperforms single-command cycle in terms of cycle time. To deal with the trade-off between the storage space cost and the operational cost of the S/R machine, we develop a decision model for finding an optimal fill-grade factor to minimise the total cost. We find the condition when an optimal fill-grade factor exists and show how to calculate it. Based on the decision model, we compare the performance of double-deep multi-aisle automated storage/retrieval system (AS/RSs) and single-deep single-aisle AS/RSs. The results show that double-deep multi-aisle AS/RSs outperform single-deep single-aisle AS/RSs in terms of total cost, although double-deep multi-aisle AS/RSs need more storage locations. [ABSTRACT FROM AUTHOR]

Comparing with traditional single-deep single-shuttle automated storage/retrieval systems, double-deep dual-shuttle AS/RS have the advantages of high space utilisation and more efficient, since less number of aisles and less empty travel of S/R machine. This warehousing systems have been developed for use in factories and distribution centres. In this paper, we first develop analytical models of quadruple command cycle to estimate the performance of such system, then taking the single shuttle and dual command cycle as the benchmark model, the potential improvement by dual shuttle has been analyzed, the results show that the efficiency of the system has a significant improvement using dual shuttle S/R machine. In addition, we have extended the proposed travel time to a special case that the double empty storage locations will take place and some management insights are given. [ABSTRACT FROM PUBLISHER]

In this paper, we address the two-dimensional bin-packing (2BP) problem with variable conflict penalties, which incur if conflicting items are loaded into the same bin. Such a problem is observed in applications such as supermarket chains and automobile components transportation. The problem not only focuses on minimisation of number of bins used, but also deals with the conflict penalties at the same time. We propose a heuristic method based on the IMA algorithm and adapt it to solve this problem. A local search procedure is also designed to further improve the solutions. For instances derived from benchmark test data, the computational results indicate that the adapted IMA heuristic algorithm with local search effectively balances the number of bins used and the conflict penalties. The algorithm outperforms several adapted approaches that are well known for the 2BP problems. [ABSTRACT FROM PUBLISHER]

We study an entrepreneur's joint inventory and rationing decision if the required capital for a venture is raised in a reward-based crowdfunding campaign. The entrepreneur sets a financing target first, and then decides the rationing policy and inventory if the campaign succeeds. We investigate the whole event with a backward induction. Maximizing the profit in our inventory model, we first obtain the optimal order quantities under each rationing policy and find that surplus funding is critical for the inventory decision. Under both policies, we find that additional borrowing yields a suboptimal order quantity, that the optimal order quantity can be reached without borrowing on a working capital line, and that the entrepreneur will expense all available funds for ordering products without borrowing. Then, we compare rationing policies and analyse the optimal financing target. The results show that, compared to the "funders first" policy, the "regular consumers first" policy is more profitable and yields lower inventory. Meanwhile, we find the optimal financing target is the lower bound in the feasible zone of the funding amount, and the "funders first" policy is more likely to yield a greater financing target. Finally, we conduct numerical examples to verify these results. [ABSTRACT FROM AUTHOR]

Given increased pressure to provide short delivery times, minimising customer order throughput time is a very important objective in warehousing operations. There are many factors that may affect the performance of an order picking system, such as layout of the warehouse, the storage strategy, the routing policy, the zoning method and the batching policy. In this study, we propose a simple travel time model and analyse the effect of order batching on the expected customer order throughput time with variable time window batching. In addition, we discussed the impact of some parameters on the batch size and the expected customer order throughput time. In the practice of Wuhan Dong Hon Logistics co. Ltd, the storage rack in the warehouse has two levels: the low storage level and the high storage level. These two levels are visited by pickers and forklifts, respectively. The classification improves the performance of order picking. In this study, we build the model based on this practice. [ABSTRACT FROM AUTHOR]

The nucleoside antibiotic toyocamycin (TM) is a potential fungicide that can control plant diseases, and it has become an attractive target for research. Streptomyces diastatochromogenes 1628, a TM-producing strain, was isolated by our laboratory and was considered to be a potent industrial producer of TM. Recently, the putative TM biosynthetic gene cluster (toy cluster) in S. diastatochromogenes 1628 was found by genome sequencing. In this study, the role of toy cluster for TM biosynthesis in S. diastatochromogenes 1628 was investigated by heterologous expression, deletion, and complementation. The extract of the recombinant strain S. albus J1074-TC harboring a copy of toy cluster produced TM as shown by HPLC analysis. The Δcluster mutant completely lost its ability to produce TM. TM production in the complemented strain was restored to a level comparable to that of the wild-type strain. These results confirmed that the toy cluster is responsible for TM biosynthesis. Moreover, the introduction of an extra copy of the toy cluster into S. diastatochromogenes 1628 led to onefold increase in TM production (312.9 mg/l vs. 152.1 mg/l) as well as the transcription of all toy genes. The toy gene cluster was engineered in which the native promoter of toyA gene, toyM gene, toyBD operon, and toyEI operon was, respectively, replaced by permE ∗ or SPL57. To further improve TM production, the engineered toy gene cluster was, respectively, introduced and overexpressed in S. diastatochromogenes 1628 to generate recombinant strains S. diastatochromogenes 1628-EC and 1628-SC. After 84 h, S. diastatochromogenes 1628-EC and 1628-SC produced 456.5 mg/l and 638.9 mg/l TM, respectively, which is an increase of 2- and 3.2-fold compared with the wild-type strain. [ABSTRACT FROM AUTHOR]

Repeat buyer prediction is crucial for e-commerce companies to enhance their customer services and product sales. In particular, being aware of which factors or rules drive repeat purchases is as significant as knowing the outcomes of predictions in the business field. Therefore, an interpretable model with excellent prediction performance is required. Many classifiers, such as the multilayer perceptron, have exceptional predictive abilities but lack model interpretability. Tree-based models possess interpretability; however, their predictive performances usually cannot achieve high levels. Based on these observations, we design an approach to balance the predictive and interpretable performance of a decision tree with model distillation and heterogeneous classifier fusion. Specifically, we first train multiple heterogeneous classifiers and integrate them through diverse combination operators. Then, classifier combination plays the role of teacher model. Subsequently, soft targets are obtained from the teacher and guide training of the decision tree. A real-world repeat buyer prediction dataset is utilized in this paper, and we adopt features with respect to three aspects: users, merchants, and user–merchant pairs. Our experimental results show that the accuracy and AUC of the decision tree are both improved, and we provide model interpretations of three aspects. [ABSTRACT FROM AUTHOR]

Multi-deep automated storage and retrieval systems (AS/RSs) have seen many implementations in warehouses due to their high floor space utilization. However, the rack size, which will fundamentally affect the operating efficiency of the storage and retrieval machine in the system, should be optimized analytically. While extensive studies have been made to analyze the system performance and optimize operating policies for single-deep and double-deep AS/RSs by travel-time models. No analytical models are available for multi-deep AS/RSs. To fill this gap, we develop travel-time models for this system, considering the random storage policy and two class-based storage policies in a multi-deep AS/RS: the one that zoning only on picking face and the one that zoning on both picking face and the depth direction. Based on the travel-time models, we derive the formulation of the optimal system size, to minimize the expected travel time of S/R machine. Simulation models are built to validate the analytical models and the results show that the maximum relative error between analytical result and simulation result is 4.3%. Numerical experiments are conducted to find the optimal size of a multi-deep AS/RS and compare the performance of these storage policies. The results show that class-based storage policy always outperform the random storage policy in terms of expected travel time, and the class-based storage policy that zoning on both picking face and the depth direction may not be better than that only zoning on the picking face, while it may be harder to handle in the system. [ABSTRACT FROM AUTHOR]

The nucleoside antibiotic toyocamycin (TM), which was produced by Streptomyces diastatochromogenes 1628, was found to be highly efficient against a broad range of plant pathogenic fungi. Despite its importance, little is known about the regulation TM biosynthesis. In this study, toyA, located in the TM biosynthetic gene cluster, was identified as a regulatory gene encoding a large ATP-binding regulator of the LuxR family (LAL-family). The role of toyA in TM biosynthesis in S. diastatochromogenes 1628 was investigated by gene deletion, complementation, and over-expression. Gene disruption of toyA resulted in almost loss of TM production. TM production in complemented strain was restored to the level comparable to that in the wild-type strain S. diastatochromogenes 1628. Over-expression of toyA separately controlled by promoter SPL57, SPL21, and permE* in wild-type strain S. diastatochromogenes 1628 led to a 2-fold, 1-fold, and 80% increase in TM production compared with wild-type strain S. diastatochromogenes 1628, respectively. Quantitative RT-PCR analysis revealed that the transcriptional level of toy structural genes was downregulated in the ΔtoyA mutant but restored in complemented strain and further upregulated in the toyA over-expression strain. The detection results from GFP reporter system in Escherichia coli and GUS reporter system and GUS activities in S. albus J1074 and S. diastatochromogenes 1628 showed that ToyA activated the expression of toyB and toyE operon directly and activated the expression of other toy structural genes indirectly. These results indicate that ToyA is essential for TM biosynthesis controlling the expression of structural genes. [ABSTRACT FROM AUTHOR]

We study a new multiple-lift compact automated parking system, which is a new technology with a circular structure using carousel equipped with the shuttles for the horizontal movement and multiple lifts equipped with the platforms for the vertical movement. This paper investigates dedicated and random shuttles operating policies. We divided the carousel into areas based on the number of lifts. We propose a dedicated shuttle operating policy under which each area shuttles can only serve one dedicated lift. A random shuttle operating policy under which shuttles can serve any lift. We get expected throughput time models for the two shuttle operating policies under the same system physical configurations based on queuing network models. We compare the analytical models with simulation models, and the results show that the proposed models provide accurate estimates. A numerical experiment is conducted to illustrate the trade-offs between dedicated shuttle and random shuttle operating policies. The results show that the retrieval time in random shuttle operating policy is larger than the retrieval time in dedicated shuttle operating policy. We also get the optimal system structure, including the number of the lifts. [ABSTRACT FROM AUTHOR]

Robotic compact storage and retrieval systems (RCSRS) have seen many implementations over the last few years. In such a system, the inventory items are stored in bins, organized in a grid. In each cell of the grid, a certain number of bins are stored on top of each other. Robots with transport and lifting capabilities move on the grid roof to transport bins between manual workstations and storage stacks. We estimate performance and evaluate storage policies of RCSRS, considering both dedicated and shared storage policies coupled with random and zoned storage stacks. Semi-open queuing networks (SOQNs) are built to estimate the system performance, which can handle both immediate and delayed reshuffling processes. We approximate the models by reduced SOQNs with two load-dependent service nodes and use the matrix-geometric method to solve them. Both simulations and a real case are used to validate the analytical models. Assuming a given number of stored products, our models can be used to optimize not only the length-to-width ratio of the system but also the stack height, depending on the storage strategy used. For a given inventory and optimal system configuration, we demonstrate that the dedicated storage policy outperforms the shared storage policy when the objective is to minimize dual command throughput time. However, from a cost perspective, with a maximum dual command throughput time as a constraint, we show that shared storage substantially outperforms dedicated storage. The annualized costs of dedicated storage are up to twice as large as those of shared storage, as a result of the larger number of storage positions required by dedicated storage and the relatively lower filling degree of storage stacks. The online appendix is available at https://doi.org/10.1287/trsc.2017.0786. [ABSTRACT FROM AUTHOR]

In today's competitive manufacturing market, effective production planning and scheduling are crucial to streamline production and increase profit. Successful production planning can achieve efficient capacity utilization and fulfill customer demand in a timely manner. For assemble-to-order companies, the assembly production planning is mainly driven by customer orders. In literature, the master production schedule which assigns production orders of individual models to production intervals is generally treated independently from the product sequencing, which might lead to local optimization for the final assembly schedule. In this paper, both order scheduling and mixed-model sequencing are taken into account simultaneously to formulate the final assembly schedule. Three objectives are concurrently considered including, maximizing net profit earned from orders, reducing sequence-dependent setup time between different models and leveling material usage. A novel multi-objective hybrid artificial bee colony (MHABC) algorithm combined with some steps of genetic algorithm and the Pareto optimality is developed to solve the current problem. Experiments are conducted and performance of the proposed MHABC algorithm is examined with the improved strength Pareto evolutionary algorithm (SPEA2). The results indicate that the proposed MHABC performs better as compared to the SPEA2 and gives better Pareto optimal solutions. Finally, a practical case problem from an engineering machinery company is solved with the proposed approach for simultaneous order scheduling and mixed-model sequencing. [ABSTRACT FROM AUTHOR]

In conventional automated storage and retrieval systems (AS/RS), storage and retrieval (S/R) machine travels simultaneously in the horizontal and vertical directions. However, S/R machine cannot support overly heavy loads, such as sea containers, so a new AS/RS, called split-platform AS/RS (SP-AS/RS), was introduced and studied in recent years. The SP-AS/RS employs vertical and horizontal platforms, which move independently, and are capable of handling heavy loads. The vertical platform which represents an elevator (or lift) with the elevator's lifting table carries the load up and down among different tiers and the horizontal platform which represents the shuttle carrier or the shuttle vehicle can access all cells of the tier in which it belongs to. Single command cycle (SC) and dual command cycle (DC) are two main operating modes in AS/RSs. However, travel time models in all previous articles related to the SP-AS/RS are only for the SC. In this study, we first present a continuous travel time model for the DC in the SP-AS/RS under input and output (I/O) dwell point policy and validate its accuracy by computer simulations. Our model and simulation results both show that the square-in-time rack incurs the smallest expected travel time. After comparing with the existing model for the SC, we find that the DC is better than the SC in terms of the expected travel time. [ABSTRACT FROM AUTHOR]

Actinomycetes have received considerable attention as biocontrol agents against fungal plant pathogens and as plant growth promoters. In this study, a total of 320 actinomycetes were isolated from various habitats in China. Among which, 77 strains have been identified as antagonistic activities against Fusarium oxysporum f. sp . cucumerinum which usually caused fusarium wilt of cucumber. Of these, isolate actinomycete M527 not only displayed broad-spectrum antifungal activity but also showed the strongest antagonistic activity against the spore germination of F. oxysporum f. sp . cucumerinum. In pot experiments, the results indicated that isolate M527 could promote the shoot growth and prevent the development of the disease on cucumber caused by F. oxysporum f. sp . cucumerinum. The control efficacy against seedling fusarium wilt of cucumber after M527 fermentation broth root-irrigation was up to 72.1% as compared to control. Based on 16S rDNA sequence analysis, the isolate M527 was identified as Streptomyces rimosus. [ABSTRACT FROM AUTHOR]

Modification of enzymes involved in transcription- or translation-processes is an interesting way to increase secondary metabolite production in Streptomycetes. However, application of such methods has not been widely described for strains which produce nucleoside antibiotics. The nucleoside antibiotic toyocamycin (TM) is produced by Streptomyces diastatochromogenes 1628. For improving TM production in S. diastatochromogenes 1628, the strain was spread on rifamycin-resistant (Rif) medium. Several spontaneous mutants were obtained with mutations in the rpoB gene which encodes a RNA polymerase β-subunit. The mutants which showed increased TM production were detected at a frequency of 7.5 % among the total Rif mutants. Mutant 1628-T15 harboring amino acid substitution His437Arg was the best TM producer with a 4.5-fold increase in comparison to that of the wild-type strain. The worst producer was mutant 1628-T62 which also showed a poor sporulation behavior. RT-PCR was performed to study the transcription levels of the TM biosynthetic gene toyG in the parental strain as well as in mutants 1628-T15 and 1628-T62. The transcriptional level of toyG was higher in mutant 1628-T15 than that in parental strain 1628, while much lower in mutant 1628-T62. In mutant strain 1628-T62 the expression of adpA gene, which is required for morphological differentiation, was also much lower. Our studies also indicate that the introduction of mutations into rpoB is an effective strategy to improve the production of TM which is an important nucleoside antibiotic. [ABSTRACT FROM AUTHOR]

In this paper, we present an efficient intelligent search algorithm for the two-dimensional rectangular strip packing problem. This algorithm involves three stages, namely greedy selection, local improvement, and randomized improvement. The greedy selection stage provides a good initial solution for the local improvement stage, which then tries to improve the solution by a deterministic local search. The randomized improvement stage employs a simple randomized local search process, which does not need any control parameter. Each of these three stages uses a heuristic approach to construct solutions based on an improved scoring rule and the least-waste-first strategy. Extensive experiments show that, to the best of our knowledge, our proposed algorithm performs slightly better than all previously published metaheuristics for most of the benchmark instances. [ABSTRACT FROM AUTHOR]

Toyocamycin (TM) shows antifungal activity and can be used to treat plant diseases. TM is produced by Streptomyces diastatochromogenes 1628, but the production rate is always very low. Recently, the gene toyG was cloned; however, nothing was known about the influence of toyG on TMproduction. In this study, the rational combined co-expression of toyG with frr encoding a ribosome recycling factor and vgb encoding Vitreoscilla hemoglobin was performed. Introduction of these genes in double- or triple-combination into strain S. diastatochromogenes 1628 led to greatly increased TM production. Transcription analysis revealed that higher TM production in the constructed recombinant strains resulted from an increase in transcriptional levels of toyG gene. At the end, among all these different recombinant strains, the strain S. diastatochromogenes 1628-VGF, harboring vgb, frr, and toyG placed under the control of PermE*, exhibited the largest increase in TM production. Notably, TM produced by S. diastatochromogenes 1628-VGF reached the highest level of 319.2 mg/L at 72 h, while TM yield of the original strain 1628 was 147.1 mg/L at 84 h. The high-yield, energy-saving strain 1628-VGF constructed in this study shall be beneficial for the industrial production of TM. [ABSTRACT FROM AUTHOR]

Data communication service has an important influence on e-commerce. The key challenge for the users is, ultimately, to select a suitable provider. However, in this article, we do not focus on this aspect but the viewpoint and decision-making of providers for order allocation and pricing policy when orders exceed service capacity. It is a multiple criteria decision-making problem such as profit and cancellation ratio. Meanwhile, we know realistic situations in which much of the input information is uncertain. Thus, it becomes very complex in a real-life environment. In this situation, fuzzy sets theory is the best tool for solving this problem. Our fuzzy model is formulated in such a way as to simultaneously consider the imprecision of information, price sensitive demand, stochastic variables, cancellation fee and the general membership function. For solving the problem, a new fuzzy programming is developed. Finally, a numerical example is presented to illustrate the proposed method. The results show that it is effective for determining the suitable order set and pricing policy of provider in data communication service with different quality of service (QoS) levels. [ABSTRACT FROM PUBLISHER]

Background: Myasthenia gravis (MG), a chronic neuromuscular disorder, can adversely affect patients' health-related quality of life (HRQoL), especially in women. The study aimed to evaluate the difference in HRQoL of women and men MG patients and explore the factors that mediate the relationship between gender and HRQoL.Methods: A cross-sectional study was conducted among 1815 patients with MG in China. The revised 15-item MG quality of life scale (MG-QOL15r) was used to access patients' HRQoL in overall, physical, social and emotional domains. Socio-demographic information, diagnosis and treatment history, comorbidities, social support, active lifestyle and the MG activities of daily living scale (MG-ADL) were recorded and compared between women and men using the Student's t-test and Pearson's Chi-square test. Multivariable regression analyses were conducted to identify independent contributors to HRQoL, especially those affecting different gender.Results: On average, female patients with MG reported a lower MG-QOL15r score than the males (44.49 ± 29.10 vs 49.32 ± 29.18). The association between gender and patients' HRQoL interacted with the number of comorbidities across the overall, physical and social domains of patients. As the number of comorbidities increased, the scores of HRQoL decreased and it was faster among females than the males (p < 0.05). Moreover, unemployment, exacerbation of the disease, and active lifestyle contributed to the patients' HRQoL across all domains. Unemployment (β = - 4.99 [95%CI, - 7.80 to - 2.18], p < 0.001) and exacerbations (β = - 8.49 [95%CI, - 11.43 to - 5.54], p < 0.001) were correlated with poorer HRQoL; while an active lifestyle had a positive impact on HRQoL (β = 0.28 [95%CI, 0.16 to 0.40], p < 0.001).Conclusions: The results indicate that the HRQoL of women MG patients was lower than that of men. The relationship between gender and HRQoL is modulated by the number of comorbidities. Thus, to improve the HRQoL of women MG patients, symptomatic treatments might not be enough, their comorbid conditions should be considered as well. Additionally, employment status, MG exacerbations, and an active lifestyle have been found as determining factors of the patients' HRQoL, which suggests future interventions should cope with these factors to improve their quality of life. [ABSTRACT FROM AUTHOR]