The sharing economy has developed rapidly in recent years using both business‐to‐customer (B2C) and customer‐to‐customer (C2C) models. This has exerted a profound impact on incumbent firms that ...follow a traditional sales model. Although the effects of B2C or C2C sharing in certain scenarios have been studied by prior literature, the effect of external B2C sharing has not been considered. Furthermore, the possible distinction between the two sharing effects as well as incumbent firms’ decisions on the sales and sharing models under the internal and external environments have not been addressed. This study compares the effects of B2C and C2C sharing in an internal sharing scenario where an incumbent firm can extend into the sharing business. Due to the difference in sharing agents, we also consider an external sharing scenario where an independent entrant firm can provide B2C or C2C sharing and strategically set price. From the perspectives of product cost and sharing transaction cost, we present several new managerial insights to expand on existing literature. First, under the internal sharing scenario, interestingly, the incumbent firm benefits from extending into the B2C or C2C sharing business only when the product cost is above a threshold, and it prefers to extend into the C2C sharing business unless the per‐period transaction cost of C2C sharing is much higher than that of B2C sharing. In addition, it is shown that the incumbent firm may need to produce more products for sales, or maintain lower sharing supply when it extends into the B2C sharing business than those when it extends C2C sharing, which is somewhat counter‐intuitive. Under the external sharing scenario, we observe that the B2C sharing business benefits the incumbent firm merely when the product cost is high, similar to the impact of C2C sharing. Meanwhile, if the per‐period transaction cost of C2C sharing is much higher than that of B2C sharing, then the positive impact of external B2C sharing on the incumbent firm’s profitability should be stronger than that of external C2C sharing. Moreover, external B2C sharing actually increases the sales demand of the incumbent firm under the conditions of low product cost and high sharing transaction cost, while external C2C sharing might increase it as well in the condition of high product cost. Both external B2C and C2C sharing may lead to a higher rental price than internal sharing in the presence of high product cost. Furthermore, even though the product cost is low, there should be higher customer surplus and total social welfare in the external B2C or C2C sharing scenarios. For constructing a comprehensive framework of sharing scenarios, we also extend our model to a setting where the incumbent firm could extend both B2C and C2C sharing in the internal and external environments. It is shown that the incumbent firm always extends into the sharing business to compete against the entrant firm in the external sharing scenario.
This paper investigates a competitive two-agent parallel-batching scheduling problem with aging effect on parallel machines. The objective is to minimize the makespan of agent
A
with the constraint ...that the makespan of agent
B
is no more than a given threshold. Some key structural properties are first identified in two different cases, and based on these structural properties a novel decision tree of scheduling rules is constructed and a heuristic algorithm is designed. Then, an effective hybrid BF-VNS algorithm combining Bacterial Foraging (BF) with variable neighborhood search (VNS) is developed to tackle the studied problem. Computational experiments are conducted to evaluate the performance of the proposed hybrid algorithm and some other well-known algorithms. The experimental results indicate that the hybrid BF-VNS algorithm performs quite better than the compared algorithms.
This paper addresses a serial-batching scheduling problem where the jobs with arbitrary release times are scheduled on parallel machines with the objective to minimize the makespan. The effects of ...learning and deterioration are considered simultaneously, and each job’s actual processing time depends on the sum of previous jobs’ processing times and the position of the current job. Each machine can process up to
c
jobs in the manner of serial batch, i.e., one after another with a setup time for each batch. Structural properties are identified for the special cases of the studied problem. Based on these derived structural properties, we propose a novel hybrid SC-VNS algorithm to solve the studied problem, which combines Society and Civilization (SC) algorithm with Variable Neighborhood Search (VNS). Computational experiments are conducted to evaluate the performance of the proposed hybrid algorithm and some other well-known algorithms. The results demonstrate that the proposed hybrid SC-VNS algorithm performs quite better than the compared algorithms in terms of the solution quality and the required running time.
This paper investigates the coordinated scheduling problem of production and transportation in a two-stage supply chain, where the actual job processing time is a linear function of its starting ...time. During the production stage the jobs are first processed in serial batches on a bounded serial batching machine at the manufacturer's site. Then, the batches are delivered to a customer by a single vehicle with limited capacity during the transportation stage, and the vehicle can only deliver one batch at one time. The objective of this proposed scheduling problem is to make decisions on job batching and batch sequencing so as to minimize the makespan. Moreover, we consider two different models. With regards to the scheduling model with a buffer for storing the processed batches before transportation, we develop an optimal algorithm to solve it. For the scheduling model without buffer, we present some useful properties and develop a heuristic H for solving it. Then a novel lower bound is derived and two optimal algorithms are designed for solving two special cases. Furthermore, computational experiments with random instances of different sizes are conducted to evaluate the proposed heuristic H, and the results show that our proposed algorithm is superior to other four approaches in the literature. Besides, heuristic H in our experiments can effectively and efficiently solve both small-size and large-size problems in a reasonable time.
•For the scheduling problem with a buffer, an optimal algorithm is developed for solving it.•For the scheduling problem without buffer, some useful properties are derived.•A heuristic is designed for solving it, and a novel lower bound is also derived.•Two special cases are well analyzed, and two optimal algorithms are developed for solving them, respectively.
Ultrasonic vibration was introduced into the solidification of the AZ91 magnesium alloy. The coarse dendrite microstructure solidified in the AZ91 alloy without any ultrasonic vibration. However, the ...microstructure with fine uniform non-dendrite grains was achieved with ultrasonic vibration. According to the analysis of refinement mechanism, it indicated that due to the acoustic cavitation and flows induced by ultrasonic vibration, the most of insoluble impurity particles become active as nucleation centers and the temperature gradient near the solidification front increases, which led to the fine uniform microstructure. Besides, the AZ91 alloy produced with ultrasonic vibration exhibited the improved mechanical properties at room temperature, such as compressive yield strength (94
MPa), ultimate compressive strength (376
MPa) and fracture strain (22.0%).
Parallel-batching processing and job deterioration are universal in the real industry. Scholars have deeply investigated the problem of parallel-batching scheduling and the problem of scheduling with ...deteriorating jobs separately. However, the situations where both parallel-batching processing and job deterioration exist simultaneously were seldom considered. This paper studies the parallel-batching scheduling problem with nonlinear processing times on a single machine, and proposes several structural properties and an optimal algorithm to solve it. Based on the above properties and optimal algorithm for the single machine setting, we further study the problem of parallel-batching scheduling with nonlinear processing times under the unrelated parallel machine setting. Since the unrelated parallel machines scheduling problem is NP-hard, a hybrid SFLA-VNS algorithm combining Shuffle Frog Leap Algorithm (SFLA) with Variable Neighborhood Search Algorithm (VNS) is proposed. Computational experiments and comparison are finally conducted to demonstrate the effectiveness of the proposed algorithm.
Multiphoton excited luminescence is of paramount importance in the field of optical detection and biological photonics. Self-trapped exciton (STE) emission with self-absorption-free advantages ...provide a choice for multiphoton excited luminescence. Herein, multiphoton excited singlet/triplet mixed STE emission with a large full width at half-maximum (617 meV) and Stokes shift (1.29 eV) has been demonstrated in single-crystalline ZnO nanocrystals. Temperature dependent steady state, transient state and time-resolved electron spin resonance spectra demonstrate a mixture of singlet (63%) and triplet (37%) mixed STE emission, which contributes to a high photoluminescence quantum yield (60.5%). First-principles calculations suggest 48.34 meV energy per exciton stored by phonons in the distorted lattice of excited states, and 58 meV singlet-triplet splitting energy for the nanocrystals being consistent with the experimental measurements. The model clarifies long and controversial debates on ZnO emission in visible region, and the multiphoton excited singlet/triplet mixed STE emission is also observed.
Maintenance cost of aircraft engine is an important component of aircraft operation cost. The prediction of aircraft engine maintenance cost can provide decision support for airline to make ...reasonable maintenance plan and maintenance fund management. Considering that the prediction accuracy of engine maintenance cost is not high in the case of small samples, this paper proposes a bootstrapped support vector regression (SVR) prediction method based on improved recursive feature elimination, which realizes the point and interval prediction of engine maintenance cost in aircraft operation phase. First, the recursive feature elimination (RFE) is improved and then combined with SVR to select feature subsets. Second, particle swarm optimization (PSO) algorithm is applied to optimize the improved RFE-SVR model (IRFE-SVR) parameters. Finally, the point and interval estimates are obtained by bootstrapped IRFE-SVR. To demonstrate the performance of the bootstrapped IRFE-SVR, experiments on UCI and a real case study of engine maintenance cost prediction are conducted. The results on UCI and real datasets show that the bootstrapped IRFE-SVR method has high accuracy and reliability.
In coastal saline lands, organic matter is scarce and saline stress is high. Exploring the promotion effect of intervention with organic acid from biological materials on soil improvement and thus ...forage output and determining the related mechanism are beneficial to the potential cultivation and resourceful, high-value utilization of coastal mudflats as back-up arable land.
Three exogenous organic acids humic acid (H), fulvic acid (F), and citric acid (C) were combined with four kinds of biomass materials cottonseed hull (CH), cow manure (CM), grass charcoal (GC), and pine needle (PN) and applied to about 0.3% of medium-salt mudflat soil. The salinity and nutrient dynamics of the soil and the growth and physiological differences of sweet sorghum at the seedling, elongation, and heading stages were observed under different treatments to screen for efficient combinations and analyze the intrinsic causes and influencing mechanisms.
The soil salinity, nutrient dynamics, and forage grass biological yield during sweet sorghum cultivation in saline soils differed significantly (
< 0.05) depending on the type of organic acid-biomass composite applied. Citric acid-pine needle composite substantially reduced the soil salinity and increased the soil nutrient content at the seedling stage and improved the root vigor and photosynthesis of sweet sorghum by increasing its stress tolerance, allowing plant morphological restructuring for a high biological yield. The improvement effect of fulvic acid-pine needle or fulvic acid-cow manure composite was manifested at the elongation and heading stages.
Citric acid-pine needle composite promoted the growth of saline sweet sorghum seedlings, and the effect of fulvic acid-pine needle composite lasted until the middle and late stages.
Smart manufacturing is an effective way to improve the efficiency of resource utilization and reduce the response time of making joint decisions for the enterprises. Though, with the globalization of ...manufacturing enterprises, manufacturing optimization problems often occur in complex manufacturing systems under the deteriorating and fuzzy environment, which brings many challenges to smart manufacturing, such as the lack of coordinating scheduling strategies to guarantee the low latency requirement. This paper investigates a robust parallel-batching scheduling problem with fuzzy processing time and past-sequence-dependent delivery time. Some structural properties are first identified, and an optimal algorithm is further developed for the single-machine scheduling problem. Then, the problem is proved to be NP-hard. We thus design a hybrid Multi-Verse Optimizer-Variable Neighborhood Search algorithm to solve the investigated problem in a reasonable time. Abundant experiments of different scales are conducted to verify the performance of the proposed hybrid method with a comparison of the state-of-the-art methods. The proposed hybrid meta-heuristic shows excellent results, robustness, and computational time performance under various experiments.
