Browsing by Author "Zhu, Tianyuan"

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    Bullwhip Effect in the Oil and Gas Supply Chain
    (2021-07-06) Zhu, Tianyuan; Balakrishnan, Jaydeep; da Silveira, Giovani JC; Alp, Osman; Zhao, Rong; Beaulieu, Eugene C; Peng, Xiaosong (David)
    The bullwhip effect refers to the phenomenon where demand variability is amplified from downstream to upstream in the supply chain. My thesis consists of three studies investigating the bullwhip effect in different types of companies in the North American oil and gas supply chain. The first study of my thesis investigates the factors that impact the bullwhip effect in the oil and gas supply chain using case study evidence from six companies, covering refining and marketing, exploration and production, integrated oil and gas, and drilling. It is found that the existing theories of the bullwhip effect have limitations in explaining the phenomenon in the oil and gas industry. Information sharing, a widely advocated countermeasure of the bullwhip effect, may not be relevant in the integrated oil and gas company. The analysis also suggests that the bullwhip effect in companies involved in the oil and gas exploration and development activities mainly exists in orders of capital items or services related to capital investments. Financial factors considered in the capital budgeting process, such as the oil price and cash flow, play an important role in determining order quantities in these companies. Therefore, the second study of my thesis quantifies the firm-level bullwhip effect in orders of capital items or services related to capital investments, and examines the impacts of oil price and cash flow variabilities on the bullwhip effect in exploration and production, drilling, and oilfield service companies. The results show that the relationships between oil price variability and bullwhip effect and between cash flow variability and bullwhip effect are both non-linear and more complicated than previously proposed. The third paper of my thesis explores the relationship between the firm-level bullwhip effect in orders of capital items or services related to capital investments and firm performance in exploration and production, drilling, and oilfield service companies. Different from the previous results obtained in the manufacturing industries, it is found that the highest firm performance is not achieved when the bullwhip effect is largely smoothed, and the bullwhip effect influences the firm performance on the income side rather than the asset side.
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    Bullwhip effect in the oil and gas supply chain : a multi-case study
    (Elsevier, 2019-11) Zhu, Tianyuan; Balakrishnan, Jaydeep; da Silveira, Giovani J. C.
    The bullwhip effect has been extensively studied in the retail, wholesale and manufacturing industries. However, it has been rarely explored in the context of resource extraction industries such as oil and gas, despite their economic impact and distinct features. This paper investigates the factors that impact the bullwhip effect in the oil and gas supply chain using case study evidence from six companies in North America, which cover refining and marketing, exploration and production, integrated oil and gas, and drilling. For each type of company studied, the operational causes of the bullwhip effect proposed in the literature and other factors of influence are examined. The findings indicate that the existing theories of the bullwhip effect have limitations in explaining the phenomenon in the oil and gas industry. Information sharing, a widely advocated countermeasure of the bullwhip effect may not be relevant in the integrated oil and gas company. Regarding the factors that drive or mitigate the bullwhip effect in different types of companies in the oil and gas supply chain, seven propositions are developed and several additional findings are obtained. All of these results enable better understandings of the bullwhip effect in academia, oil and gas organisations and related industries, and may provide guidance for potential countermeasures in practice.
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    Recent advances in dynamic facility layout research
    (INFOR: Information Systems and Operational Research, 2017-09-08) Zhu, Tianyuan; Balakrishnan, Jaydeep; Cheng, Chun-Hung
    It has been nearly two decades since the last major review of the literature in dynamic facility layout. In these intervening years, many advances have been made in modelling as well as in the solution methods. In this study, models and solutions that address the dynamic facility layout problem (DFLP) are examined and categorized. Our review finds that the recent DFLP models consider more complex design features and constraints. Further, only a few DFLP studies have adopted exact methods, while most of the effective algorithms used are heuristics, metaheuristics and hybrid approaches. Future research directions are also identified.