B2C e-commerce logistics network optimization model

In this paper, considering the characteristics of e-commerce logistics and the problems arising from the construction of logistics network, based on the full investigation and research of the B2C electricity supplier operation mode, we have studied and summarized the research results of scholars at home and abroad aiming at the related problems, and summarized and summarized the methods and steps of logistics network optimization in the whole country. First, we established the logistics network structure.The definition of network level, node function and connection between nodes is carried out. Then, through the improved urban agglomeration order gravity model, the scope of self logistics city is screened. Finally, the link of logistics network structure is scheduled for completion with the goal of cost optimization.

B2C E-Commerce Logistics Network Optimization Model

In this paper, considering the characteristics of e-commerce logistics and the problems arising from the construction of logistics network, based on the full investigation and research of the B2C electricity supplier operation mode, we have studied and summarized the research results of scholars at home and abroad aiming at the related problems, and summarized and summarized the methods and steps of logistics network optimization in the whole country. First, we established the logistics network structure.The definition of network level, node function and connection between nodes is carried out. Then, through the improved urban agglomeration order gravity model, the scope of self logistics city is screened. Finally, the link of logistics network structure is scheduled for completion with the goal of cost optimization.

The Determinants of Vietnam’s Information and Communication Technologies Exports to the European Union

Vietnam is one of the top information and communication technologies (ICT) exporters globally, and the ICT products constitute nearly one-fifth of Vietnam’s total exports to the European Union (EU). This study empirically investigates the determinants of Vietnam’s ICT exports to the EU by applying the gravity model for trade with panel data from 2000 to 2019. Besides the traditional variables of the gravity model, we added gross capital formation, patent application and exchange rates as explanatory variables. The results show that among factors affecting Vietnam’s ICT export to the EU, market size, patent applications, and exchange rate are the most significant determinants. The article also suggests some policy implications for the development of ICT exports between the two parties. JEL Codes: F14, C2

Road infrastructure and intra-community trade in the Central African Economic and Monetary Community

We examine the contribution of domestic and interstates road infrastructures to trade flow between member countries of the Central African Economic and Monetary Community (CEMAC). Theories of international economics as well as those of the new economic geography suggest a positive contribution of both road infrastructures to intraregional trade. A gravity model of international trade is estimated to evaluate this theoretical prediction in the CEMAC zone. Results confirm a positive contribution of interstate road infrastructure to intra-Community trade, but show no evidence of a positive contribution of domestic road infrastructure to intra- CEMAC trade.

Improved gravity model for identifying the influential nodes

Identifying the influential nodes in network is essential for network dynamic analysis. In this letter, inspired by the gravity model, we present an improved gravity model (EDGM) to identify the influential nodes in network through the effective distance. Firstly, we calculate the degree of nodes. Then we construct the effective distance combined with the interaction frequency between nodes, so as to establish the effective distance gravity model. Comparing with the susceptible-infected model, the results show that the Kendall' s $\tau$ correlation coefficient of EDGM could enhanced by 2.36\% for the gravity model. Compared with other methods, the Kendall' s $\tau$ correlation coefficient of EDGM could enhanced by 11.55%, 17.29%, 7.17% and 10.00% for the degree centrality, betweenness centrality, eigenvector centrality, and PageRank respectively. The results show that the improved gravity model could effectively identify the influential nodes in network.

No-go theorem for inflation in an extended Ricci-inverse gravity model

In this paper, we propose an extension of the Ricci-inverse gravity, which has been proposed recently as a very novel type of fourth-order gravity, by introducing a second order term of the so-called anticurvature scalar as a correction. The main purpose of this paper is that we would like to see whether the extended Ricci-inverse gravity model admits the homogeneous and isotropic Friedmann–Lemaitre–Robertson–Walker metric as its stable inflationary solution. However, a no-go theorem for inflation in this extended Ricci-inverse gravity is shown to appear through a stability analysis based on the dynamical system method. As a result, this no-go theorem implies that it is impossible to have such stable inflation in this extended Ricci-inverse gravity model.