Centralized versus Decentralized Inventory Control in Supply Chains and the Bullwhip Effect

This paper constructs a model of a supply chain to examine how demand volatility is passed upstream through the chain. In particular, we seek to determine how likely it is that the chain experiences a bullwhip effect, where the variance of the upstream firm’s production exceeds the variance of the downstream firm’s sales. We show that the bullwhip effect is more likely to occur and is greater in size in supply chains in which inventory control is centralized rather than decentralized, that is, exercised by the downstream firm

Does vertical integration increase product quality?

Numerous product quality scandals are caused by low-quality inputs. When input quality is not perfectly observed by downstream firms, upstream firms often have moral hazard problems. If vertical integration does not directly eliminate the moral hazard problems, does vertical integration still improve product quality? If so, under which conditions? We find that given the precision of monitoring technology used by downstream firms, when the level of public monitoring is very high or very low, downstream firms have no incentive to integrate upstream firms; when the level is intermediate, downstream firms have incentives to integrate and vertical integration increases product quality

Three Essays on the Role of Intermediaries

This dissertation aims at further enhancing our understanding of how intermediaries can in different scenarios affect supplier’s behavior and what determines their effects on the economy and social welfare

Turning Flowchart into Dialog: Plan-based Data Augmentation for Low-Resource Flowchart-grounded Troubleshooting Dialogs

Flowchart-grounded troubleshooting dialogue (FTD) systems, which follow the instructions of a flowchart to diagnose users' problems in specific domains (eg., vehicle, laptop), have been gaining research interest in recent years. However, collecting sufficient dialogues that are naturally grounded on flowcharts is costly, thus FTD systems are impeded by scarce training data. To mitigate the data sparsity issue, we propose a plan-based data augmentation (PlanDA) approach that generates diverse synthetic dialog data at scale by transforming concise flowchart into dialogues. Specifically, its generative model employs a variational-base framework with a hierarchical planning strategy that includes global and local latent planning variables. Experiments on the FloDial dataset show that synthetic dialogue produced by PlanDA improves the performance of downstream tasks, including flowchart path retrieval and response generation, in particular on the Out-of-Flowchart settings. In addition, further analysis demonstrate the quality of synthetic data generated by PlanDA in paths that are covered by current sample dialogues and paths that are not covered

A Multiobjective Computation Offloading Algorithm for Mobile Edge Computing

In mobile edge computing (MEC), smart mobile devices (SMDs) with limited computation resources and battery lifetime can offload their computing-intensive tasks to MEC servers, thus to enhance the computing capability and reduce the energy consumption of SMDs. Nevertheless, offloading tasks to the edge incurs additional transmission time and thus higher execution delay. This paper studies the trade-off between the completion time of applications and the energy consumption of SMDs in MEC networks. The problem is formulated as a multiobjective computation offloading problem (MCOP), where the task precedence, i.e. ordering of tasks in SMD applications, is introduced as a new constraint in the MCOP. An improved multiobjective evolutionary algorithm based on decomposition (MOEA/D) with two performance enhancing schemes is proposed.1) The problem-specific population initialization scheme uses a latency-based execution location initialization method to initialize the execution location (i.e. either local SMD or MEC server) for each task. 2) The dynamic voltage and frequency scaling based energy conservation scheme helps to decrease the energy consumption without increasing the completion time of applications. The simulation results clearly demonstrate that the proposed algorithm outperforms a number of state-of-the-art heuristics and meta-heuristics in terms of the convergence and diversity of the obtained nondominated solutions

A Review of the Indicators for Assessing the Sustainability of Urban Regeneration

The prevailing urban regeneration practices have shown the irreplaceable role in solving certain social and urban problems. However, the lack of an overall assessment tool to evaluate the overall sustainability of urban regeneration projects has led to many unsustainable issues during the large- scale urban regeneration around the world. Thus, it is deemed necessary to assess the performance of urban regeneration based on specific indicators. Many indicator-based assessment tools for evaluating urban regeneration have been built, but none of them is applicable to all countries due to social, historic, economic, cultural differences. Based on the literature review about sustainable urban renewal in major databases, this research first presents a critical review of recent studies on sustainable urban renewal, then identifies the main indicators for evaluating the economic, environmental and social sustainability of urban regeneration, and summarizes the common indicators used in evaluating urban regeneration performance. Finally, this paper suggests the establishment of indicator-based sustainability assessment framework which has a wide scope of application