Xusen Cheng, Jian Mou, Xiao-Liang Shen, Triparna de Vreede and Rainer Alt
Yaqin Zhang, Mingming Wang, Ruimin Wang, Zhipeng Li and Nan Zhang
This paper aims to reschedule the freight train timetable in case of disturbance to restore the train services as soon as possible.
Abstract
Purpose
This paper aims to reschedule the freight train timetable in case of disturbance to restore the train services as soon as possible.
Design/methodology/approach
Hence, an integer linear programming model for the real-time freight heavy-haul railway traffic management is developed in case of large primary delays caused by the delayed cargos loading. The proposed model based on the alternative graph at the microscopic level depicts the freight train movements in detail. Multiple dispatching measures such as re-timing and re-ordering are taken into account. Moreover, two objective functions, namely, the total final delays and the consecutive delays, are minimized in the freight trains dispatching problem.
Findings
Finally, a real-world computational experiment based on the Haolebaoji-Ji’an freight heavy-haul railway is implemented. The results of all disrupted cases are obtained within 10 s. The results give insight into that the consecutive delays are more than the total final delays when the same disrupted situation and the consecutive or total final delays increase as the primary delays increase.
Originality/value
An integer linear programming model based on the alternative graph for the real-time freight heavy-haul railway traffic management is developed in case of large primary delays caused by the delayed cargos loading. The method can be developed as the computer-aided tool for freight train dispatchers.
Details
Keywords
Weijie Tan, Xihui Chen, Mingming Teng, Weidong An and Changhua Wu
Green Public Procurement (GPP) is a crucial way to promote producing green products, but its relationship with corporate pollution emissions needs to be verified. This study aims…
Abstract
Purpose
Green Public Procurement (GPP) is a crucial way to promote producing green products, but its relationship with corporate pollution emissions needs to be verified. This study aims to evaluate the environmental effects of the policy by analyzing how GPP influences corporate environmental pollution.
Design/methodology/approach
This study is based on extensive sample data of Chinese industrial enterprises from 2001 to 2010, using China’s first GPP list as an exogenous policy. The authors have established a differential model to explore the impact of GPP on corporate environmental pollution and its underlying mechanisms.
Findings
GPP significantly reduces the sulfur dioxide (SO2) emissions of enterprises. Verify the robustness of this conclusion by replacing variables, excluding other policy interventions that reduce selfselection bias, and conducting placebo testing. GPP encourages regulated enterprises to improve their production processes, drive clean production with green technology innovation, optimize energy structure, improve energy efficiency and reduce their emissions. The environmental cleaning effect of GPP is more significant in eastern and central China large and medium-sized urban areas. GPP has more effectively reduced SO2 emissions from private capital-intensive and heavily polluting enterprises.
Originality/value
This paper constructs a difference-in-differences model to study China’s first GPP list in 2006. It explores how GPP policies affect corporate pollution reduction. The findings enrich GPP research in China and emerging economies. Moreover, unlike existing studies on corporate pollution subject to environmental regulation, this paper focuses on how corporate pollution reduction is affected by demand-driven GPP policies, expanding the theoretical research.
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Keywords
Shiyi Chen and Wang Li
With China’s economic growth slowing down and the growth rate of fiscal revenue decreasing, the pressure on local government debts is further increasing. Under this background, it…
Abstract
Purpose
With China’s economic growth slowing down and the growth rate of fiscal revenue decreasing, the pressure on local government debts is further increasing. Under this background, it is of great significance to clarify the relation between local government debts and China’s economic growth in order to give full play to the positive role of local debts in stabling growth. The paper aims to discuss this issue.
Design/methodology/approach
Therefore, this paper explores the impact of Chinese local government debt on economic growth from theoretical and empirical aspects, respectively, and compares the regional differences between different debts and economic growth dynamics.
Findings
In the theoretical model part, this paper constructs a three-sector dynamic game model, under the two circumstances of whether local government is subject to debt constraints, and examines the relation between local government debt and economic growth and other variables through numerical simulation. Research shows that when the government is not constrained by debt, there is an inverted “U” relation between government debt and economic growth. When the government is constrained by debt, the economic growth rate gradually decreases as the government debt increases.
Originality/value
In the theoretical analysis part, this paper tries to estimate the amount of local debts under different calibers and examines the impact of different types of local government debts on China’s economic growth and their regional differences. The results show that excessive accumulation of government hidden debts in the eastern region is not conducive to economic growth, while explicit debts in the central and western regions significantly contribute to local economic growth. The results of empirical analysis are basically consistent with the predictions of the theoretical model.