Question C: E-commerce logistics network package emergency dispatch and structural optimization
The e-commerce logistics network is composed of logistics sites (receiving warehouses, sorting centers, sales departments, etc.) and transportation lines between logistics sites, as shown in Figure 1. Affected by holidays and promotional activities such as "Double Eleven" and "618", the order volume of e-commerce users will fluctuate significantly, and when emergencies such as epidemics and earthquakes cause temporary or permanent suspension of logistics venues, the handling The parcels will be urgently diverted to other logistics sites. These factors will affect the number of packages transported by each route, as well as the distribution of each logistics site.
The number of packages processed.
Figure 1 Schematic diagram of e-commerce logistics network
If the number of packages (hereinafter referred to as cargo volume) in each logistics site and route can be predicted, managers will be able to arrange transportation, sorting and other plans in advance, thereby reducing operating costs and improving operational efficiency. In particular, when some sites are temporarily or permanently out of service, designing a logistics network adjustment plan based on the forecast results and the processing capacity of each logistics site and the transportation capacity of the line will greatly reduce the impact of the outage of the logistics site on the logistics network. Ensure the normal operation of the logistics network.
Attachment 1 shows the volume data of a logistics network that flows between different logistics sites every day from 2021-01-01 to 2022-12-31. The logistics network has 81 logistics sites and 1049 routes. The lines are directional, for example, the line DC1→DC2 and the line DC2→DC1 are considered as two
lines. It is assumed that the processing capacity of each logistics site and the upper limit of the transportation capacity of each route are the maximum historical cargo volume.
Based on the above background, ask your team to complete the following questions:
Question *1* : Establish a prediction model for the cargo volume of the line, predict the daily cargo volume of each line from 2023-01-01 to 2023-01-31, and give the line DC14→DC10, DC20 in the submitted paper →The prediction results of DC35, DC25→DC62.
Question *2* : If the logistics site DC5 starts to shut down on 2023-01-01, please build a mathematical model based on the prediction in question 1, and allocate the cargo volume of DC5 related lines to other lines so that all packages can flow as normally as possible , and make the number of lines whose cargo volume changes before and after the shutdown of DC5 as few as possible, and keep the workload of each line as balanced as possible. If there are some days and part of the volume of goods that are not normally circulated, your diversion plan should also make the daily cumulative total of parcels that fail to circulate normally during the period from 2023-01-01 to 2023-01-31 as small as possible. For normal circulation, please give the number of lines whose cargo volume changes due to the shutdown of DC5 and the network load situation; for normal circulation, please give the number of lines for which cargo volume has changed due to the shutdown of DC5, and the cargo that cannot be normally circulated. volume and network load.
Question *3* : In Question 2, if the closed logistics site is DC9, and dynamic adjustments to the logistics network structure are allowed (daily adjustments are possible), the adjustment measures are closing or opening new lines, excluding new additions For the logistics site, it is assumed that the upper limit of the transportation capacity of the newly opened line is the maximum value of the transportation capacity of the existing line. Please allocate the cargo volume of DC9-related lines to other lines, so that all packages can flow as normal as possible, and make the number of lines whose cargo volume changes before and after DC9 shut down be as small as possible, and keep the workload of each line as balanced as possible. If there is a transfer plan that does not meet the requirements on some dates, your diversion plan should also make the cumulative daily total of parcels that cannot be transferred normally during the period from 2023-01-01 to 2023-01-31 as small as possible. During normal circulation, please give the details of the goods caused by the shutdown of DC9.
The number of lines whose traffic volume changes and the network load situation; when the normal flow cannot be performed, please give the number of lines whose cargo volume has changed due to the shutdown of DC9, the cargo volume that cannot be normally circulated, and the network load situation; at the same time, please give the daily Line increase and decrease.
Question *4* : According to Annex 1, please evaluate the importance of different logistics sites and routes of the network; in order to improve network performance, if you plan to add new logistics sites and routes, combined with the prediction results of Question 1, discuss and analyze the new Which new lines should be added between the logistics site and the existing logistics sites, how should the processing capacity of the new logistics site and the transportation capacity of the new line be set? Considering the randomness of the prediction results, please further explore the robustness of the network you built.