Container yard allocation and transfer scheduling optimization method for intermodal transportation

Abstract

The application provides a port station container bay assignment and transfer scheduling optimization method for water-railway combined transportation, and relates to the technical field of railway port station container bay assignment and transfer optimization.The application collects relevant information of to-be-assigned containers, stored containers in a yard, yard bays and yard container transportation paths, constructs a coupling optimization model with container area operation container quantity balance and minimum total container transportation distance as objective functions, and cooperatively optimizes container bay assignment plans and transfer plans in the port yard and the railway yard.The method realizes reasonable arrangement of container bays and transfer plans on the basis of comprehensive consideration of port-port station yard characteristics in the water-railway combined operation process, coordinates dynamic transfer yard double operation processes of water-sea and sea-railway two-way containers, and improves the storage operation efficiency of the port station.

Description

Technical Field

[0001] This invention relates to the field of railway port station container space allocation and transshipment optimization technology that takes into account the characteristics of rail-water intermodal transport organization, specifically to a port station container space allocation and transshipment scheduling optimization method for rail-water intermodal transport. Background Technology

[0002] Currently, rail-water intermodal transport, by seamlessly connecting rail and water transport, leverages the combined advantages of both—large capacity, low cost, low energy consumption, and low pollution—becoming a new mode of transportation that optimizes cargo transport structure and reduces social logistics costs. Among the many aspects of rail-water intermodal transport, container space allocation directly determines yard utilization and loading / unloading efficiency: reasonable container space allocation can shorten waiting times for trains and ships, reduce container handling and empty runs, achieving optimal "time-cost" efficiency. This is a key aspect of efficient rail-water intermodal transport, and optimizing container space allocation has thus become a research hotspot.

[0003] However, existing optimization methods still have the following shortcomings.

[0004] 1. Most existing optimization methods for container space allocation still focus on a single yard layout rather than a dual yard layout for rail-water intermodal transport. Furthermore, some optimization methods for dual yard scenarios in rail-water intermodal transport do not take into account the characteristics of the rail-water intermodal transport scenario.

[0005] 2. Existing optimization methods for container space allocation lack the ability to handle two-way container flows of both imported and exported containers.

[0006] 3. Existing optimization methods for container space allocation only optimize the container stacking process and do not consider the complex transshipment process after container stacking, which does not conform to the reality of container transportation. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the present invention provides an optimization method for container space allocation and transshipment scheduling at port stations for rail-water intermodal transport. Based on the basic rules of container stacking, this method comprehensively considers the characteristics of port stations and port yards in rail-water intermodal operations and various transshipment situations in the actual container transportation process. It coordinates the dynamic transfer and dual operation process of rail-sea and sea-rail bidirectional containers, and proposes an optimization method for container space allocation and transshipment scheduling at port stations for rail-water intermodal transport. This solves the problem that existing optimization methods only focus on stacking and ignore the efficiency of subsequent transshipment scheduling.

[0008] The technical means employed in this invention are as follows: An optimization method for container space allocation and transshipment scheduling at port stations for rail-water intermodal transport includes the following steps: Step 1: Obtain arrival and departure time data of containers to be allocated, departure time and occupied space data of already stored containers, space layout and quantity data of the two yards, and container transport route distance data; construct an overall objective function based on the obtained data; Step 2: Determine the space availability status of the two yards at the initial planning time based on the space availability data of already stored containers; allocate initial space to containers to be allocated based on the space availability status of the two yards at the initial planning time; obtain the arrival time and transport distance of each container to be allocated at the initial space. Step 3: Based on the availability of container slots in both yards and the remaining time before departure for each container, select subsequent transfer routes for containers with initial slots under the transfer rules. Then calculate the transportation distance of each container from the last slot to the ship or train. At the same time, determine whether there is a second slot for containers with initial slots. If so, allocate a second slot to them. The second slot refers to the slot occupied by the container during the period from leaving the initial slot to departure, excluding the slot occupied by yard crane operations and truck transportation. Step 4: Based on the different transfer routes after each container leaves the initial slot... Step 5: Calculate the arrival time of containers with a confirmed second location at the second location, and then calculate the transportation distance between the two locations. For containers without a second location, calculate their arrival time on the ship or train. Step 6: Calculate the departure time of containers with a confirmed second location from the second location. For containers without a second location, specify their departure time from the ship or train. Step 7: Impose restrictions on the container location status and changes at any time during the planning period, calculate the objective function value, and finally obtain the solution to the container location assignment and transshipment scheduling problem. Among these, the container location status at any time during the planning period... The restrictions on changes include: (1) at any time, any container slot can only change from idle to non-idle or from non-idle to idle due to the arrival or departure of a container; (2) at any time, it is not allowed for the upper container slot to be non-idle while the lower container slot is idle; (3) the number of containers stacked cannot exceed the maximum layer limit; (4) the number of containers stacked cannot exceed the maximum capacity limit of the container area; (5) if any two adjacent container slots are both non-idle at a certain time, they cannot both change to idle at the next time.

[0009] Compared with the prior art, the present invention has the following advantages.

[0010] This invention outlines the basic process of container transportation in sea-rail intermodal transport. Based on the basic rules of container storage, it comprehensively considers the characteristics of port stations and port yards in sea-rail intermodal operations and various transshipment situations in the actual container transportation process. It realizes joint optimization of container space allocation and transshipment scheduling, and proposes a more efficient and practical container operation process. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a flowchart of a method for optimizing the allocation and transshipment scheduling of container slots at port stations for rail-water intermodal transport, as described in an embodiment of the present invention. Detailed Implementation

[0013] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0014] like Figure 1 As shown, this invention provides an optimization method for container space allocation and transshipment scheduling at port stations for rail-water intermodal transport, comprising the following steps: Step 1: Obtain arrival and departure time data for containers to be allocated, departure time and occupied space data for already stored containers, space layout and quantity data for the two container yards, and container transport route distance data to construct the overall objective function. The overall objective function of the model is defined as: (1) In the formula, Let be the overall objective function. This is a collection of imported containers awaiting allocation. A collection of export containers awaiting allocation. This refers to the collection of imported containers that have already been stored. This refers to the collection of already stored export containers. This is a variable representing the maximum number of containers handled in each container area. Let be the variable representing the minimum number of containers handled in each container area. To indicate containers The variable is the total transport distance. The overall objective function consists of two parts: the range of container volume in each container area and the total container transport distance.

[0015] Step 2: Based on the data of container slots already occupied by stacked containers, determine the availability of container slots in the two yards at the beginning of the planning period (time 0). Then, allocate initial container slots to the containers to be allocated, and obtain the arrival time and transportation distance of each container to be allocated to its initial slot, as well as the number of containers handled in each container area.

[0016] In a preferred embodiment of the present invention, allocating initial container slots for containers to be allocated includes the following steps: Step 2.1: Based on the data of container spaces occupied by the stacked containers, determine the status of container spaces in the two yards as empty or occupied at the beginning of the planning period (time 0).

[0017] Specifically, the container position status at time 0 is determined by equations (2) and (3): (2) (3) In the formula, It is a variable that takes the value of 0 or 1, representing the container position in the port yard at time 0. The status is 0 when the container space is empty and 1 when the container space is occupied; It is a variable that takes the value of 0 or 1, representing the position of the container in the railway yard at time 0. The status is 0 when the container slot is empty and 1 when the container slot is occupied. For the collection of bay berths in the port yard. A collection of storage spaces in the port yard. For the set of layers in the port storage yard, For the collection of bays in the railway storage yard, A collection of stacking positions for railway storage yards. This refers to the set of layers in a railway storage yard. This is a parameter that takes the value 0 or 1, indicating that containers have been stacked at time 0. Is it a container space in the port yard? If yes, it is 1; otherwise, it is 0. This is a parameter that takes the value 0 or 1, indicating that containers have been stacked at time 0. Is it in the container yard? If yes, it is 1; otherwise, it is 0.

[0018] Step 2.2: Based on the available container space information in the two yards, and on the basis of satisfying the initial location selection preferences of different types of containers to be allocated and the basic rules of container space allocation, assign initial container spaces to the containers to be allocated.

[0019] Specifically, Equation (4) represents the basic rule that any container to be allocated can only have an initial container location in either the port yard or the railway yard, and that there can only be one initial container location: (4) In the formula, It is a variable that takes the value 0 or 1, representing a container. Is the initial container location the port yard? If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing a container. Was the initial container location the railway yard? If yes, it is 1; otherwise, it is 0.

[0020] Equations (5) and (6) represent the initial location selection preference, that is, to allocate as many imported containers as possible to the railway yard as possible, and to allocate as many exported containers as possible to the port yard as possible: (5) (6) In the formula, and It is an adjustable parameter greater than or equal to 1; It is the set of stacks in the railway storage yard that are closest to the railway. In the railway yard, except for the stacks Other than the stack set, they are all A subset of; It is the set of warehouses in the port's storage yard that are closest to the shore. In the port yard, except for the stacks Other than the stack set, they are all A subset of.

[0021] Any stacked container The initial container position can be determined from known parameters. and The value is obtained from the data. To more conveniently represent the constraints related to stacked containers in the following text, it is stipulated here that for stacked containers, variables with values ​​of 0 or 1 are also used. and This indicates the initial container position. and Relationship and The relationship is defined by equations (7) and (8): (7) (8) Step 2.3: The time when any container to be allocated arrives at its initial location can be calculated using equations (9) and (10) after its initial location is determined: (9) (10) In the formula, This indicates containers awaiting allocation. The variable representing the time when the container reaches its initial position. This is a parameter representing the containers to be allocated. Arrival time This is a parameter representing the bay position from the ship to the port yard. Stack distance, This is a parameter representing the distance from the ship to the railway yard. Stack distance, This is a parameter representing the bay position from the train to the port yard. Stack distance, This is a parameter representing the distance from the train to the railway yard. Stack distance, This is a parameter representing the truck's travel speed. This is a parameter that indicates the duration of container operations performed by quay cranes, yard cranes, and rail-mounted gantry cranes.

[0022] It must be greater than Equation (11) represents The upper limit of the range of values: (11) In the formula, These are parameters representing containers. The departure time.

[0023] Step 2.4: After determining the initial container location and the time of arrival at the initial container location, determine the values ​​of the decision variables with a time dimension related to the arrival at the initial container location.

[0024] Specifically, the values ​​of the time-dependent decision variables related to reaching the initial container position are determined by equations (12)-(15): (12) (13) (14) (15) In the formula, It is a collection of moments. It is a variable that takes the value 0 or 1, representing a container. Is it at the moment Reaching the initial container position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing a container. Is it at the moment Reaching the initial container position If yes, it is 1; otherwise, it is 0.

[0025] Step 2.5: After determining the initial container location of the containers to be allocated, the transportation distance from the ship or train to the initial container location for each container to be allocated can be obtained.

[0026] Specifically, the transport distance from the ship or train to the initial container position for each container to be allocated is calculated using equations (16) and (17): (16) (17) In the formula, This indicates containers awaiting allocation. The variable is the transport distance from the ship to the initial container location. After determining the initial container locations for the containers to be allocated, the container handling capacity for each container area is calculated using equations (18) and (19): (18) (19) In the formula, It is a collection of container areas in the port yard. It is a collection of container areas in a railway storage yard. It is the container yard area of ​​the port. The set of betas in the middle is a subset of It is a railway container yard area The set of betas in the middle is a subset of It is the container yard area of ​​the port. The stack set in the middle is a subset of It is a railway container yard area The stack set in the middle is a subset of It is the container yard area of ​​the port. The set of layers in the middle is a subset of It is a railway container yard area The stack set in the middle is a subset of It refers to the container area of ​​the port yard. The variable of the quantity of work boxes, This indicates the container area of ​​the railway yard. The variable is the quantity of work boxes.

[0027] Step 3: Based on the availability of container slots in both yards and the remaining time before departure for each container, select a subsequent transshipment route for containers with initial slots under the transshipment rules. This involves determining if a second slot is available; if so, assigning it. Then, calculate the transport distance for each container from its last available slot to the ship or train. The second slot refers to the slot occupied by the container during the period from leaving its initial slot to departure, excluding yard crane operations and truck transport.

[0028] In a preferred embodiment of the present invention, determining the subsequent transshipment route for a container with an existing initial container space includes the following steps: Step 3.1: Select the subsequent transfer route for containers with existing initial container slots, that is, determine whether there is a second container slot. Containers with a second container slot will be transported to the second container slot for continued storage, while containers without a second container slot will be directly transported to the ship or train.

[0029] Specifically, Equation (20) stipulates that any initial container space in the port yard for both unallocated and stored imported containers may have a second container space in the railway yard after leaving the port yard and before being loaded onto a train; any initial container space in the railway yard for both unallocated and stored imported containers must not have a second container space. (20) In the formula, These are variables that take values ​​of 0 or 1, representing imported containers awaiting allocation and imported containers already stored. Is the second container location a railway storage yard? If yes, it is 1; otherwise, it is 0.

[0030] Equation (21) stipulates that any initial container space in the railway yard for an unassigned export container and a stored export container may have a second container space in the port yard after leaving the railway yard and before being loaded onto the ship; any initial container space in the port yard for an unassigned export container and a stored export container must not have a second container space: (twenty one) In the formula, It is a variable that takes the value 0 or 1, representing the export containers to be allocated and the export containers already stored. Is the second container bay in the port yard? If yes, it is 1; otherwise, it is 0.

[0031] Step 3.2: After determining the subsequent transshipment route for each container, calculate the transportation distance for each container from leaving the last container location to being transported to the ship or train.

[0032] Specifically, equation (22) is used to calculate for both imported containers to be allocated and imported containers already stored:

[0033] (twenty two) Equation (23) is used to calculate the export containers to be allocated and the export containers already stored:

[0034] (twenty three) The first part of Equations (22) and (23) is for the case where the container can have a second container space but does not select the second container space, the second part is for the case where the container cannot have a second container space to select, and the third part is for the case where the container selects the second container space.

[0035] In the formula, It refers to containers The variable of the transport distance from the last container to the train or ship. It is a parameter, indicating the position from the beta. Stack Distance to the train It is a parameter, indicating the position from the beta. Stack Distance to the train It is a parameter, indicating the position from the beta. Stack Distance to the ship It is a parameter, indicating the position from the beta. Stack Distance to the ship. It is a variable that takes the value 0 or 1, and it only applies to imported containers awaiting allocation and imported containers already in storage. The initial container position is The value is 1 when there is no second container, and 0 in other cases; It is a variable that takes the value 0 or 1, and it only applies to export containers awaiting allocation and already stacked export containers. The initial container position is Furthermore, the value is 1 when there is no second container and 0 in other cases. Equations (24)-(29) are for... and Rules for the value: (twenty four) (25) (26) (27) (28) (29) Step 4: Determine the time when each container leaves its initial location based on its different transfer routes after leaving the initial location.

[0036] In a preferred embodiment of the present invention, determining the time for a container to leave its initial location includes the following steps: Step 4.1: First, limit the values ​​of the decision variables with a time dimension that are related to leaving the initial container position.

[0037] Specifically, equations (30)-(35) indicate that any container to be allocated will definitely leave the initial container position it has reached, cannot leave the initial container position it has not reached, the time it leaves the initial container position must be later than the time it arrives at the initial container position, but not later than its departure time, it cannot leave at a time outside this interval, and there can only be one departure time: (30) (31) (32) (33) (34) (35) In the formula, It is a variable that takes the value 0 or 1, representing a container. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing a container. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0.

[0038] Equations (36)-(39) indicate that any stacked container will definitely leave the container position it was in at time 0, cannot leave a container position it was not in at time 0, the time it leaves the initial container position must be later than time 0, but not later than its departure time, cannot leave at a time outside this interval, and there can only be one departure time: (36) (37) (38) (39) In the formula, It is a variable that takes the value of 0 or 1, representing the containers that have been stacked. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value of 0 or 1, representing the containers that have been stacked. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0.

[0039] Step 4.2: Imported containers awaiting allocation and imported containers already stored in the railway yard with initial container slots have no second slots and are directly loaded onto the train; exported containers awaiting allocation and exported containers already stored in the port yard with initial container slots have no second slots and are directly loaded onto the ship.

[0040] Specifically, the time when such containers leave their initial positions is determined by equations (40)-(43): (40) (41) (42) (43) In the formula, It is a very large positive number. It refers to containers The variable at the moment of departure from the initial box position.

[0041] Step 4.3: Imported containers awaiting allocation and those already stored, whose initial container space is in the port yard and has no second container space, will be directly loaded onto the train. Exported containers awaiting allocation and those already stored, whose initial container space is in the railway yard and has no second container space, will be directly loaded onto the ship.

[0042] Specifically, the time when such containers leave their initial positions is determined by equations (44)-(47):

[0043] (44)

[0044] (45)

[0045] (46)

[0046] (47) Step 4.4: The time when a container with a second storage space leaves its initial storage space is determined by limiting the range of decision variables through the constraints in Step 4.1 and then using equation (48). The values ​​of the time-dimensional decision variables for containers without a second storage space are also determined by equation (48):

[0047] (48) Equations (49) and (50) represent the containers to be allocated and the containers already stored, respectively. The lower limit of the range of values ​​for .

[0048] (49) (50) Step 5: Calculate the arrival time of containers with a confirmed second container slot, and then calculate the transportation distance between the two slots. For containers without a second container slot, also calculate their arrival time on the ship or train.

[0049] In a preferred embodiment of the present invention, determining the arrival time of a container at a second container location after it has left its initial location includes the following steps: Step 5.1: After determining whether there is a second container space, limit the values ​​of the decision variables with a time dimension related to reaching the second container space.

[0050] Specifically, equations (51)-(56) limit the time when a container with a second container space arrives at the second container space by restricting the values ​​of decision variables with a time dimension related to arrival at the second container space. They also stipulate that the time of arrival at the second container space must be later than the time of departure from the initial container space and earlier than the time of departure from the port, and there can only be one of these times. The container cannot arrive at the second container space outside this interval. (51) (52) (53) (54) (55) (56) In the formula, These are variables that take values ​​of 0 or 1, representing imported containers awaiting allocation and imported containers already stored. Is it at the moment Arriving at the second container position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing the export containers to be allocated and the export containers already stored. Is it at the moment Arriving at the second container position If yes, it is 1; otherwise, it is 0.

[0051] Step 5.2: Calculate the arrival times of containers with a confirmed second container space and the arrival times of containers without a confirmed second container space on the ship or train.

[0052] Specifically, equations (57) and (58) determine the time when the imported containers awaiting allocation for the second container slot and the time when the already stored imported containers arrive at the second container slot: (57) (58) Equations (59) and (60) determine the time when the export containers awaiting allocation and the stacked export containers arrive at the second container location: (59) (60) In the formula, It refers to containers The variable is the time of arrival at the second box position.

[0053] After determining the arrival time of the second container, the values ​​of the decision variables with the time dimension are determined, and the results are obtained from equations (61)-(64): (61) (62) (63) (64) Equations (65)-(68) determine the arrival times of imported containers awaiting allocation and those already stored on the train when there is no second container slot: (65) (66)

[0054] (67)

[0055] (68) Equations (65) and (66) are for imported containers whose initial container space is in the railway yard, and equations (67) and (68) are for imported containers whose initial container space is in the port yard but for which there is no second container space.

[0056] Equations (69)-(72) determine the arrival times of export containers awaiting allocation and stacked export containers on the ship when there is no second container slot: (69) (70)

[0057] (71)

[0058] (72) Equations (69) and (70) are for export containers whose initial container position is in the port yard, and equations (71) and (72) are for export containers whose initial container position is in the railway yard but which do not have a second container position.

[0059] Equation (73) represents The upper limit of the range of values: (73) Step 5.3: Calculate the transport distance from the initial container location to the second container location for containers with a second container location.

[0060] Specifically, equation (74) determines the transport distance from the initial container position to the second container position for imported containers awaiting allocation and imported containers already stored, which have a second container position: (74) Equation (75) determines the transport distance from the initial container position to the second container position for export containers awaiting allocation and for already stacked export containers with a second container position: (75) In the formula, It refers to containers The variable is the transport distance from the initial container location to the second container location. It is a variable that takes the value 0 or 1, and it only applies to imported containers awaiting allocation and imported containers already in storage. In the position Stack There is an initial box position and it is in the bay position. Stack The value is 1 if there is a second box, otherwise it is 0; It is a variable that takes the value 0 or 1, and it only applies to export containers awaiting allocation and already stacked export containers. In the position Stack There is an initial box position and it is in the bay position. Stack The value is 1 if there is a second box, otherwise it is 0. This indicates from the position of the beta. Stack to bei Stack The distance parameter; This indicates from the position of the beta. Stack to bei Stack The parameter of the distance.

[0061] Equations (76)-(81) are for and Rules for the value: (76) (77) (78) (79) (80) (81) Step 6: Calculate the departure time for containers with a confirmed second container slot. For containers without a second container slot, the departure time from the ship or train must also be specified.

[0062] In a preferred embodiment of the present invention, determining the departure time of a container arriving at the second container bay includes the following steps: Step 6.1: Limit the values ​​of the decision variables with a time dimension related to leaving the second box.

[0063] Specifically, equations (82)-(87) indicate that any container will definitely leave the second container location it has arrived at, cannot leave the second container location it has not arrived at, and the time it leaves the second container location must be later than the time it arrives at the second container location, but not later than its departure time. It cannot leave at a time outside this interval, and there can only be one departure time: (82) (83) (84) (85) (86) (87) In the formula, These are variables that take the value 0 or 1, representing imported containers awaiting allocation and imported containers already stored. Is it at the moment Leave the second compartment If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing the export containers to be allocated and the export containers already stored. Is it at the moment Leave the second compartment If yes, it is 1; otherwise, it is 0.

[0064] Step 6.2: Based on the departure time of the containers, calculate the departure time of containers with a second container space and the departure time of containers without a second container space.

[0065] Specifically, equations (88) and (89) specify the times when an imported container awaiting allocation and an imported container already stored in a second container space leave the second container space: (88) (89) Equations (90) and (91) specify the times when unallocated export containers with a second container slot and stacked export containers leave the second container slot: (90) (91) In the formula, It refers to containers The variable at the moment of leaving the second box.

[0066] After determining the time of departure from the second container, the values ​​of the decision variables with a time dimension related to departure from the second container are determined, and the results are obtained from equations (92)-(95): (92) (93) (94) (95) Equations (96)-(103) specify the container without a second compartment. The value of its departure time same: (96) (97) (98) (99) Equations (96) and (97) are for imported containers whose initial container space is in the railway yard, and equations (98) and (99) are for imported containers whose initial container space is in the port yard but which do not have a second container space.

[0067] (100) (101) (102) (103) Equations (100) and (101) are for export containers whose initial container position is in the port yard, and equations (102) and (103) are for export containers whose initial container position is in the railway yard but which do not have a second container position.

[0068] Equations (104) and (105) represent The lower limit of the range of values ​​for: (104) (105) Step 7: Impose constraints on the container location status and changes at any time during the planning period, calculate the objective function value, and finally obtain the solution to the container location allocation and transshipment scheduling problem. These constraints mainly include the following points.

[0069] (1) At any given time, any container space may change from idle to non-idle or from non-idle to idle only due to the arrival or departure of a container.

[0070] (2) At no time is it permissible for the upper storage compartment to be in an idle state while the lower storage compartment is in an idle state.

[0071] (3) Containers cannot be stacked beyond the maximum number of layers.

[0072] (4) Containers shall not be stacked beyond the maximum capacity limit of the container area.

[0073] (5) If any two adjacent boxes are both in a non-idle state at a certain moment, they cannot both change to an idle state at the next moment. If they are both in an idle state at a certain moment, they cannot both change to a non-idle state at the next moment.

[0074] In a preferred embodiment of the present invention, limiting the state and changes of the container position and calculating the objective function value includes the following steps: Step 7.1: Equations (106)-(109) specify that the idle state of a container space at two adjacent moments will change due to the arrival or departure of containers, and only one of these changes can occur at any given moment for any container space:

[0075] (106)

[0076] (107)

[0077] (108)

[0078] (109) In the formula, It is a variable that takes the value 0 or 1, representing the time interval [0, 1]. Box location The status is 0 if the container is empty and 1 if it is not empty; It is a variable that takes the value 0 or 1, representing the time interval [0, 1]. Box location The status is 0 if the container is empty and 1 if it is not empty.

[0079] Step 7.2: Equations (110) and (111) stipulate that at any given time, the upper-level container slot cannot be occupied while the lower-level container slot is empty: (110) (111) Step 7.3: Equations (112) and (113) stipulate that the number of layers of containers cannot be exceeded: (112) (113) Step 7.4: Equations (114) and (115) stipulate that container stacking cannot exceed the maximum capacity of the container area: (114) (115) Step 7.5: Equations (116)-(119) stipulate that if any two adjacent boxes are both in a non-empty state at a certain moment, they cannot both change to an idle state at the next moment. If both are in an idle state at a certain moment, they cannot both change to a non-empty state at the next moment.

[0080] (116) (117) (118) (119) Step 7.6: Calculate the value of the objective function.

[0081] Specifically, equations (120)-(124) calculate the range of the number of boxes handled in the box area and impose restrictions on the range: (120) (121) (122) (123) (124) In the formula, It is an adjustable parameter.

[0082] Equations (125) and (126) are used to calculate the total transport distance of the container: (125) (126) The method provided in this embodiment can efficiently solve the container space allocation and transshipment scheduling problems in the rail-water intermodal transport scenario. With the design goals of balancing the number of containers in each container area and minimizing the total transport distance of containers, it considers finding the optimal container space and transshipment route for containers among the links of container ship-port yard-station yard-train, and rationally decides the arrival time and departure time of container space, so as to achieve efficient integration of container space allocation and transshipment scheduling, thereby making efficient use of yard container space resources and maximizing the advantages of the port-station dual yard layout.

[0083] In summary, the port station container space allocation and transshipment scheduling optimization method for rail-water intermodal transport provided by this invention has the following advantages compared with the prior art.

[0084] 1. This invention takes into account the dual-yard layout characteristics of port yards and terminal yards in the context of rail-water intermodal transport, and introduces a two-way operation process for imported and exported containers. Compared with the previous operation process that only considered a single yard layout and a single-direction container flow, the problem scenario solved by this invention is more complex and more in line with reality.

[0085] 2. Based on the dual-yard layout of port yard and terminal yard and the two-way operation process of import and export containers, multiple transfer path options are considered after combining the two. In addition to the previous consideration of only assigning storage space to containers, the transfer scheduling path of containers after leaving the storage space is also planned, making the container operation process more dynamic and realizing the coupling of multiple units and multiple links.

[0086] 3. The importance of the time dimension in the container operation process is considered. By combining container operation time with container yard space, the container location assignment and transfer scheduling optimization process is made more accurate and effective.

[0087] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport, characterized in that, Includes the following steps: Step 1: Obtain arrival and departure time data of containers to be allocated, departure time and occupied container space data of already stored containers, container space layout and quantity data of the two yards, and container transportation route distance data. Construct the overall objective function based on the obtained data. Step 2: Based on the data of container slots occupied by the stacked containers, determine the availability of container slots in the two yards at the initial planning time. Based on the availability of container slots in the two yards at the initial planning time, assign initial container slots to the containers to be assigned, and obtain the time and transportation distance of each container to be assigned to the initial container slot, as well as the number of containers handled in each container area. Step 3: Based on the availability of container slots in the two yards and the remaining time before departure for each container, select the subsequent transfer route for containers with initial slots under the transfer rules. Then calculate the transportation distance of each container from the last slot to the ship or train. At the same time, determine whether containers with initial slots have a second slot. If so, allocate a second slot to them. The second slot refers to the slot occupied by the container during the time from leaving the initial slot to departure, excluding the slots occupied by yard crane operations and truck transportation. Step 4: Determine the time of departure from the initial container location for each container based on its different transfer routes after leaving the initial container location; Step 5: Calculate the arrival time of containers with a confirmed second container space, and then calculate the transportation distance between the two container spaces. For containers without a second container space, calculate the arrival time of the container on the ship or train. Step 6: Calculate the departure time of containers with a confirmed second container space, and stipulate the departure time of containers without a second container space from the ship or train. Step 7: Impose constraints on the container location status and changes at any time during the planning period, calculate the objective function value, and finally obtain the solution to the container location allocation and transshipment scheduling problem; the constraints on the container location status and changes at any time during the planning period include: (1) At any given time, any container slot may change from idle to non-idle or from non-idle to idle only due to the arrival or departure of a container. (2) At no time is it permissible for the upper storage compartment to be in a non-idle state while the lower storage compartment is in an idle state. (3) Containers cannot be stacked beyond the maximum number of layers. (4) Containers must not be stacked beyond the maximum capacity limit of the container area. (5) If any two adjacent boxes are both in a non-idle state at a certain moment, they cannot both change to an idle state at the next moment. If they are both in an idle state at a certain moment, they cannot both change to a non-idle state at the next moment.

2. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, The overall objective function is: （1） In the formula, Let be the overall objective function. This is a collection of imported containers awaiting allocation. A collection of export containers awaiting allocation. This refers to the collection of imported containers that have already been stored. This refers to the collection of already stored export containers. This is a variable representing the maximum number of containers handled in each container area. Let this be a variable representing the minimum number of containers handled in each container area. To indicate containers The variable is the total transport distance.

3. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, Based on the availability of container spaces in the two yards at the initial planning stage, initial container spaces are allocated to the containers to be allocated, including the following steps: Step 2.1: Based on the container space data already occupied by stacked containers, the initial state of the container spaces in the two yards—whether they are empty or occupied—is determined by the following constraints: (2) (3) In the formula, It is a variable that takes the value of 0 or 1, representing the container position in the port yard at time 0. The status is 0 if the container slot is empty, and 1 if the container slot is occupied. It is a variable that takes the value of 0 or 1, representing the position of the container in the railway yard at time 0. The status is 0 if the container slot is empty, and 1 if the container slot is occupied. For the collection of bay berths in the port yard. A collection of storage spaces in the port yard. For the set of layers in the port storage yard, For the collection of bays in the railway storage yard, A collection of stacking positions for railway storage yards. This refers to the set of strata in a railway storage yard. This is a parameter that takes the value 0 or 1, indicating that containers have been stacked at time 0. Is it a container space in the port yard? If yes, it is 1; otherwise, it is 0. This is a parameter that takes the value 0 or 1, indicating that containers have been stacked at time 0. Is it in the container yard? If yes, it is 1; otherwise, it is 0. Step 2.2: Based on the available container space information in the two yards, and while satisfying the basic rules for container space allocation and the initial location selection preferences for different types of containers to be allocated, assign initial container spaces to the containers to be allocated: The following constraints represent the basic rule that any container to be allocated can only have an initial location in either the port yard or the railway yard, and that there can only be one initial location: (4) In the formula, It is a variable that takes the value 0 or 1, representing a container. Is the initial container location the port yard? If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing a container. Was the initial container location the railway yard? If yes, it is 1; otherwise, it is 0. The initial location selection preference is set to prioritize the initial location of imported containers to be allocated in the railway yard as much as possible, and to prioritize the initial location of exported containers to be allocated in the port yard as much as possible, as indicated by the following constraints: (5) (6) In the formula, and It is an adjustable parameter greater than or equal to 1. It is the set of stacks in the railway storage yard that are closest to the railway. In the railway yard, except for the stacks Other than the stack set, they are all a subset of It is the set of warehouses in the port yard that are closest to the shore. In the port yard, except for the stacks Other than the stack set, they are all a subset of Any stacked container The initial container position can be determined from known parameters. and The value is obtained from the data, and for already stacked containers, variables with values ​​of 0 or 1 are also used. and This indicates the initial container position. and Relationship and The relationship is defined by the following constraints: (7) (8) Step 2.3: The arrival time of any container to be allocated at its initial location can be determined by the following constraints after its initial location is determined: (9) (10) In the formula, This indicates containers awaiting allocation. The variable representing the time when the container reaches its initial position. This is a parameter representing the containers to be allocated. Arrival time This is a parameter representing the bay position from the ship to the port yard. Stack distance, This is a parameter representing the distance from the ship to the railway yard. Stack distance, This is a parameter representing the bay position from the train to the port yard. Stack distance, This is a parameter representing the distance from the train to the railway yard. Stack distance, This is a parameter representing the truck's travel speed. These are parameters that indicate the duration of container operations performed by quay cranes, yard cranes, and rail-mounted gantry cranes. It must be greater than The following constraints indicate The upper limit of the range of values: (11) In the formula, These are parameters representing containers. Departure time; Step 2.4: After determining the initial container location and the time of arrival at the initial container location, the following constraints determine the values ​​of the time-dependent decision variables related to arrival at the initial container location: (12) (13) (14) (15) In the formula, It is a collection of moments. It is a variable that takes the value 0 or 1, representing a container. Is it at the moment? Reaching the initial container position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing a container. Is it at the moment? Reaching the initial container position If yes, it is 1; otherwise, it is 0. Step 2.5: After determining the initial container locations for each container to be allocated, the transport distance from the ship or train to the initial location is calculated based on the following constraints: (16) (17) In the formula, This indicates containers awaiting allocation. The variable is the transport distance from the ship to the initial container location. After determining the initial container locations for the containers to be allocated, the container throughput for each container area is calculated based on the following constraints: (18) (19) In the formula, It is a collection of container areas in the port yard. It is a collection of container areas in a railway storage yard. It is the container yard area of ​​the port. The set of betas in the middle is a subset of It is a railway container yard area The set of betas in the middle is a subset of It is the container yard area of ​​the port. The stack set in the middle is a subset of It is a railway container yard area The stack set in the middle is a subset of It is the container yard area of ​​the port. The hierarchical set in the middle is a subset of It is a railway container yard area The stack set in the middle is a subset of It refers to the container area of ​​the port yard. The variable of the quantity of work boxes, This indicates the container area of ​​the railway yard. The variable is the quantity of work boxes.

4. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, Based on the availability of container slots in both yards and the remaining time before departure for each container, subsequent transshipment routes are selected for containers with existing initial slots under the transshipment rules, including: Step 3.1: Select a subsequent transshipment route for containers with existing initial slots, determine if there are second slots available, and if so, transport containers to those slots for continued storage; otherwise, transport containers directly to a ship or train. The following constraints stipulate that any initial container space in the port yard for both unassigned and stored imported containers may have a second container space in the railway yard after leaving the port yard and before being loaded onto a train; however, any initial container space in the railway yard for both unassigned and stored imported containers will never have a second container space: (20) In the formula, These are variables that take the value 0 or 1, representing imported containers awaiting allocation and imported containers already stored. Is the second container location a railway storage yard? If yes, it is 1; otherwise, it is 0. The following constraints stipulate that any initial container space in the railway yard for both unassigned and stored export containers may have a second container space in the port yard after leaving the railway yard but before being loaded onto the ship; however, any initial container space in the port yard for both unassigned and stored export containers will never have a second container space: (21) In the formula, It is a variable that takes the value 0 or 1, representing the export containers to be allocated and the export containers already stored. Is the second container bay in the port yard? If yes, it is 1; otherwise, it is 0. Step 3.2: After determining the subsequent transshipment route for each container, calculate the transportation distance for each container from leaving the last container slot to being transported to the ship or train. The calculation result is determined by the following constraints: Imported containers awaiting allocation and imported containers already in storage: (22) Export containers awaiting allocation and already stored export containers: (23) In the formula, It refers to containers The variable of the transport distance from the last container to the train or ship. It is a parameter, indicating the position from the beta. Stack Distance to the train It is a parameter, indicating the position from the beta. Stack Distance to the train It is a parameter, indicating the position from the beta. Stack Distance to the ship It is a parameter, indicating the position from the beta. Stack Distance to the ship It is a variable that takes the value 0 or 1, and it only applies to imported containers awaiting allocation and imported containers already in storage. The initial container position is The value is 1 when there is no second container, and 0 in other cases. It is a variable that takes the value 0 or 1, and it only applies to export containers awaiting allocation and already stacked export containers. The initial container position is The value is 1 when there is no second container, and 0 otherwise. The following constraints apply to... and Rules for the value: (24) (25) (26) (27) (28) (29)。 5. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, Based on the different transit routes of each container after leaving its initial location, determine the time of departure from the initial location, including: Step 4.1: First, limit the time of departure from the initial container by specifying the values ​​of the decision variables with a time dimension related to leaving the initial container position: The following constraints state that any container to be allocated must leave its initial location that it has reached, cannot leave its initial location that it has not reached, its departure time must be later than its arrival time at the initial location, but not later than its departure time, it cannot leave at a time outside this interval, and there can only be one departure time: (30) (31) (32) (33) (34) (35) In the formula, It is a variable that takes the value 0 or 1, representing a container. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing a container. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0. The following constraints state that any stacked container will definitely leave the container position it was in at time 0, cannot leave a container position it was not in at time 0, its departure time must be later than time 0 but not later than its departure time, it cannot leave at a time outside this interval, and it can only leave at one time: (36) (37) (38) (39) In the formula, It is a variable that takes the value of 0 or 1, representing the containers that have been stacked. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value of 0 or 1, representing the containers that have been stacked. Is it at the moment Leave the initial box position If yes, it is 1; otherwise, it is 0. Step 4.2: For imported containers awaiting allocation and those already stored in the railway yard with no second available space, they are directly loaded onto the train; for exported containers awaiting allocation and those already stored in the port yard with no second available space, they are directly loaded onto the ship. The time when these containers leave their initial space is determined by the following constraints: (40) (41) (42) (43) In the formula, It is a very large positive number. It refers to containers The variable at the moment of departure from the initial box position; Step 4.3: Import containers awaiting allocation and already stored containers with initial storage locations in the port yard and no second storage location will be directly loaded onto trains. Export containers awaiting allocation and already stored containers with initial storage locations in the railway yard and no second storage location will be directly loaded onto ships. The time when these containers leave their initial storage locations is determined by the following constraints: (44) (45) (46) (47) Step 4.4: The time when a container with a second storage space leaves its initial storage space is determined by limiting the range of decision variables through the constraints in Step 4.1, and then by the following constraints. The values ​​of the time-dimensional decision variables for containers without a second storage space are also determined by the following constraints: (48) The following two formulas represent the containers to be allocated and the containers already stored, respectively. The lower limit of the range of values ​​of (49) (50)。 6. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, Calculate the arrival time of containers with a confirmed second container slot, including: Step 5.1: After determining whether a container has a second storage space, the following constraints limit the arrival time of a container with a second storage space by restricting the values ​​of decision variables with a time dimension related to arrival at the second storage space. It also stipulates that the arrival time at the second storage space must be later than the time it left its initial storage space and earlier than its departure time, and there can only be one of these times; the container cannot arrive at the second storage space outside this interval: (51) (52) (53) (54) (55) (56) In the formula, These are variables that take values ​​of 0 or 1, representing imported containers awaiting allocation and imported containers already stored. Is it at the moment Arriving at the second container position If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing the export containers to be allocated and the export containers already stored. Is it at the moment Arriving at the second container position If yes, it is 1; otherwise, it is 0. Step 5.2: Calculate the arrival times of containers with a confirmed second container slot and the arrival times of containers without a confirmed second container slot on the ship or train. The results are obtained from the following constraints: The arrival times of imported containers awaiting allocation at the second container slot and of already stored imported containers at the second container slot: (57) (58) The arrival times of export containers awaiting allocation at the second container slot and of already stored export containers at the second container slot: (59) (60) In the formula, It refers to containers The variable of the time of arrival at the second box position. After determining the arrival time of the second container, the values ​​of the decision variables with a time dimension are determined, and the results are obtained from the following constraints: (61) (62) (63) (64) There is no second container slot. The arrival time of imported containers awaiting allocation and those already stored on the train is determined by the following constraints: (65) (66) (67) (68) There is no second container slot. The arrival time of export containers awaiting allocation and stacked export containers loaded onto the ship is determined by the following constraints: (69) (70) (71) (72) The following constraints represent The upper limit of the range of values: (73) Step 5.3: Calculate the transport distance from the initial container location to the second container location for containers with a second container location. The calculation result is derived from the following constraints: The transport distance from the initial container position to the second container position for imported containers awaiting allocation and imported containers already stacked with a second container slot: (74) The transport distance from the initial container location to the second container location for export containers awaiting allocation and for already stacked export containers: (75) In the formula, It refers to containers The variable is the transport distance from the initial container location to the second container location. It is a variable that takes the value 0 or 1, and it only applies to imported containers awaiting allocation and imported containers already in storage. In the position Stack There is an initial box position and it is in the bay position. Stack The value is 1 if there is a second container slot, and 0 otherwise. It is a variable that takes the value 0 or 1, and it only applies to export containers awaiting allocation and already stacked export containers. In the position Stack There is an initial box position and it is in the bay position. Stack The value is 1 if there is a second container slot, and 0 otherwise. This indicates from the position of the beta. Stack to bei Stack The distance parameter; This indicates from the position of the beta. Stack to bei Stack The distance parameter, The following constraints are for and Rules for the value: (76) (77) (78) (79) (80) (81)。 7. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, Calculate the time when a container with a confirmed second container slot leaves that slot, including: Step 6.1: The following constraints state that any container will definitely leave the second container location it has arrived at, cannot leave the second container location it has not arrived at, the time of its departure from the second container location must be later than the time of its arrival at the second container location, but not later than its departure time, cannot leave at a time outside this interval, and can only have one departure time: (82) (83) (84) (85) (86) (87) In the formula, These are variables that take the value 0 or 1, representing imported containers awaiting allocation and imported containers already stored. Is it at the moment? Leave the second compartment If yes, it is 1; otherwise, it is 0. It is a variable that takes the value 0 or 1, representing the export containers to be allocated and the export containers already stored. Is it at the moment? Leave the second compartment If yes, it is 1; otherwise, it is 0. Step 6.2: Based on the container departure time, calculate the departure time of containers with a second container space and the departure time of containers without a second container space. The results are subject to the following constraints: The times when imported containers awaiting allocation in the second container slot and imported containers already stored leave the second container slot: (88) (89) The times when unallocated export containers in the second container slot and stacked export containers leave the second container slot: (90) (91) In the formula, It refers to containers The variable at the moment of leaving the second box position. After determining the time of departure from the second bin, the values ​​of the time-dependent decision variables related to departure from the second bin are determined, and the results are obtained from the following constraints: (92) (93) (94) (95) Containers without a second compartment are subject to regulations. The value of its departure time same: (96) (97) (98) (99) (100) (101) (102) (103) The following constraints represent The lower limit of the range of values ​​for: (104) (105)。 8. The method for optimizing container space allocation and transshipment scheduling at port stations for rail-water intermodal transport according to claim 1, characterized in that, Constraints are imposed on the container position status and changes at any time during the planning period, and the objective function value is calculated, including: Step 7.1: The following constraints stipulate that the idle state of a container space at two adjacent moments will change due to the arrival or departure of containers, and only one of these changes can occur at any given moment for any container space: (106) (107) (108) (109) In the formula, It is a variable that takes the value 0 or 1, representing the time interval [0, 1]. Box location The status is 0 if the container is empty and 1 if it is not empty; It is a variable that takes the value 0 or 1, representing the time interval [0, 1]. Box location The status is 0 if the container is empty and 1 if it is not empty; Step 7.2: The following constraint stipulates that at any given time, the upper-level container slot cannot be occupied while the lower-level container slot is empty: (110) (111) Step 7.3: The following constraints stipulate that containers cannot be stacked beyond the maximum number of layers: (112) (113) Step 7.4: The following constraints stipulate that container stacking cannot exceed the maximum capacity of the container area: (114) (115) Step 7.5: The following constraint stipulates that if any two adjacent storage units are both non-empty at a certain moment, they cannot both become idle at the next moment; if both are idle at a certain moment, they cannot both become non-empty at the next moment. (116) (117) (118) (119) Step 7.6: The calculation results of the two parts of the objective function—the range of container volume in each container area and the total container transport distance—are obtained from the following constraints: (120) (121) (122) (123) (124) (125) (126) In the formula, It is an adjustable parameter.

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