| Author: | Zou, Ding |
| Title: | Issues on managing sustainable operations |
| Advisors: | Guo, Xiaomeng (LMS) Pan, Kai (LMS) Wang, Yulan (LMS) |
| Degree: | Ph.D. |
| Year: | 2022 |
| Subject: | Local transit -- Simulation method Recycled products -- Purchasing -- Simulation methods Mathematical optimization Operations research Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Logistics and Maritime Studies |
| Pages: | xii, 120 pages : color illustrations |
| Language: | English |
| Abstract: | In this thesis, we explore two issues related to efficient resource utilization to support the sustainable development goal for our society. To achieve sustainable operations, firms are encouraged to positively impact customers as well as the environment in addition to pursue profit. For example, a last-mile transportation service provider can increase the utilization of limited vehicle resource, which provides customers a convenient alternative for short-distance travel in urban area and hence helps reduce the carbon emissions from automobiles. Another example is that, a firm selling consumer product can use recycled materials that saves production resource and waste to help citizens live in a better environment. Both of them save the resource and provide customers a more sustainable lifestyle. We further elaborate the two aforementioned aspects as follows. In the first topic, we consider the efficient operations of limited amount of vehicles that can be allocated to urban area in a shared micromobility system. A micromobility service provider can crowdsource individual riders to conduct vehicle relocation with reward incentives and outsource relocation to a third-party logistics provider (3PL). The former performs vehicle relocation continuously while the latter runs the relocation following a certain schedule. We construct a time-space network with multiple regions and formulate a two-stage stochastic integer programming model incorporating riders' demand uncertainty. In the first stage, the micromobility operator plans the initial vehicle allocation across service regions, while in the second stage, he decides subsequent vehicle relocation across the regions over an operational horizon. To enable the practical significance of our model, we develop a temporal decomposition algorithm, which outperforms a state-of-the-art commercial solver in solution quality and computational time for solving large-scale problem instances based on real data. Numerical experiments show that 3PL outsourcing is more efficient for mass relocation than rider crowdsourcing, while the latter is more efficient in handling sporadic relocation needs. Introducing rider crowdsourcing in addition to 3PL outsourcing can significantly increase the profit, reduce the demand loss, and improve the vehicle utilization rate of the system without affecting the existing commitment with the 3PL. The budget for acquiring vehicles and the budget for rider crowdsourcing significantly impact the vehicles' initial allocation and subsequent relocation. We also find that rider crowdsourcing relocates more vehicles under a unimodal demand pattern than a bimodal pattern, whereas the reverse holds for 3PL outsourcing. In the second topic, we consider how the recycled materials in a sustainable product can be impacted by the recycling label. In practice, there are many different types of recycling label issued by NGOs. We consider two types of commonly observed recycling labels: 1) Percentage label that conducts a continuous grading assessment, from which consumers know exactly the fraction of recycled content; 2) Binary label that implements a pass/fail criterion, from which consumers only know whether the fraction of recycled content meets the standard or not. We establish a game-theoretical model wherein an NGO needs to decide the label type and a monopoly firm decides the fraction of recycled content and price for its product. The firm sells its product to consumers who cannot directly observe the fraction of recycled content used in the product but can obtain information from the label on the product. Some consumers are environmentally conscious who are willing to pay a premium for the recycled content; and others are environmentally unconscious who are indifferent in recycled and non-recycled content. We examine the impacts of different labelling schemes on a firm's recycling and pricing decisions as well as an NGO's payoff and consumer surplus. We highlight a few interesting findings. First, the firm weakly prefers the percentage label, while NGO and consumers weakly prefer the binary label. Second, more environmentally conscious consumers or lower fixed cost of recycling may not necessarily increase the firm's usage of recycled materials under the binary label, and may indeed hurt the consumer surplus under either label type. These findings can provide useful managerial insights for NGOs and firms who are concerned about recycled materials. |
| Rights: | All rights reserved |
| Access: | open access |
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