Methods for predicting lock throughput capacity

Abstract

This invention discloses a method for predicting the throughput capacity of a ship lock. The method involves obtaining the total cargo volume, ship type, and the proportion of cargo volume carried by each ship type for the predicted year; calculating the total number of ship trips for each ship type in the predicted year; randomly combining ship types and numbers into the same lock throughput batch; determining the platooning pattern of ships within the same throughput batch using a two-dimensional packing algorithm based on the lock's length and width and the ship's length and width; calculating the average deadweight tonnage per lock trip for each ship type in the platooning pattern that completes the predicted annual cargo volume according to the platooning pattern; and taking the maximum value among the calculated average deadweight tonnage per lock trip for several platooning patterns as the predicted annual lock throughput capacity. The advantages of this invention are its clear principle, simple calculation process, accurate results, and high efficiency, providing more precise data support for ship lock engineering design.

Description

Technical Field

[0001] This invention relates to the field of lock engineering design, and in particular to a method for predicting the throughput capacity of locks. Background Technology

[0002] Single-passage tonnage is a crucial indicator for evaluating the throughput capacity of a ship lock. Currently, the standard ship form factor method and the fleet arrangement method are commonly used to calculate single-passage tonnage. The standard ship form factor method calculates the single-passage tonnage by multiplying the maximum design ship form by a certain coefficient. However, the determination of this coefficient is rather arbitrary, leading to highly inaccurate results. The fleet arrangement method determines the single-passage tonnage by combining different ship forms and fleet arrangements. The single-passage tonnage calculated using the fleet arrangement method is more accurate than that calculated by the standard ship form factor method. However, it requires continuous trial calculations based on the passage ratio (i.e., the proportion of cargo volume carried by each ship form predicted from past data when using the fleet arrangement method to calculate the single-passage tonnage), which is quite cumbersome. Summary of the Invention

[0003] The purpose of this invention is to provide a method for predicting the throughput capacity of a ship lock, which can accurately and efficiently determine the tonnage of a single lock passage, providing more accurate data support for the design of ship lock projects.

[0004] To achieve the above objectives, the present invention adopts the following technical solution:

[0005] The method for predicting the throughput capacity of a ship lock according to the present invention includes the following steps:

[0006] S1 provides the total freight volume, ship type, and the proportion of freight volume carried by each ship type for the forecast year.

[0007] S2 calculates and predicts the total number of ship calls for each ship type in the current year;

[0008] S3, random combination of ship type and number of ships in the same lock passage batch;

[0009] S4. Based on the length and width of the lock and the length and width of the vessel, a two-dimensional packing algorithm is used to determine the formation of vessels within the same lock-passing batch.

[0010] S5, repeat steps S3 and S4 to obtain the formation of several vessels in the same lock-passing batch;

[0011] S6, calculate the predicted annual freight volume according to the formation method, and the ship type of each ship in the formation method is equal to the average deadweight tonnage of a single lock run of the total number of ships;

[0012] S7, the maximum value among the several average load tonnages of a single lock operation is the predicted annual lock throughput capacity.

[0013] Furthermore, the two-dimensional bin packing algorithm described in step S4 is as follows:

[0014] S4.1 Project the gate chamber horizontally as rectangle 1, take the lower left vertex of rectangle 1 as the origin, the length L1 direction as the X-axis, and the width W1 direction as the Y-axis to establish the gate chamber coordinate system;

[0015] S4.2, Collect the length L2 and width W2 of the vessels in the same lock passage batch; Calculate the minimum number of vessels N that can be discharged from the lock chamber based on the length L2 and width W2 of the vessel with the largest length L2 and width W2.

[0016] S4.3 When the number of ships N1 in the same lock-passing batch is less than or equal to N, the ships in the same lock-passing batch directly form one formation.

[0017] S4.4 When the number N1 of ships in the same lock-passing batch is greater than N, N+1 ships are extracted according to the ship arrangement order to form a pre-arranged queue A;

[0018] S4.5, using the coordinates of the origin of the gate chamber coordinate system as the first locating point, construct a locating point queue;

[0019] S4.6 Extract one ship B from the pre-arranged queue A, with a horizontal projection of rectangle 2 of length L2 and width W2; according to the arrangement order of the arrangement points in the arrangement point queue, place the lower left vertex of rectangle 2 at the arrangement point until an arrangement point is found that satisfies the condition that rectangle 1 completely contains rectangle 2 and there is no overlap between rectangles 2.

[0020] S4.7, Delete the available points occupied in step S4.6, and add the coordinates of the other vertices of rectangle 2 to the available point queue in order; put the ship B into the lock permutation combination C;

[0021] S4.8, repeat S4.6 and S4.7 until the pre-sorted queue A is empty;

[0022] S4.9 If other vessels in the same lock-passing batch can still fit into rectangle 1, then execute steps S4.6 and S4.7 until no other vessels in the same lock-passing batch can fit into rectangle 1.

[0023] S4.10, repeat steps S4.4 to S4.9 until the number of vessels N1 in the same lock-passing batch is 0;

[0024] S4.11, output the arrangement and combination C of several primary locks as the formation mode of ships in the same lock-passing batch.

[0025] Further, in step S4.6, if none of the available points in the available point queue can satisfy the condition that rectangle 1 completely contains rectangle 2 and there is no overlap between rectangles 2, then the vessel represented by rectangle 2 is removed from the pre-arrangement queue A, and a vessel smaller than rectangle 2 is selected from the pre-arrangement queue A or other vessels in the same lock-passing batch, and steps S4.6 and S4.7 are executed.

[0026] Further, in step S4.7, adding the coordinates of the other vertices of rectangle 2 to the queue of points to be sorted in order includes: obtaining the coordinates of each vertex of rectangle 2 except the lower left vertex in the gate chamber coordinate system; comparing any two coordinates and placing the one with the smaller x-coordinate value at the front of the queue of points to be sorted; if the x-coordinates of the two coordinates are the same, then placing the one with the smaller y-coordinate value at the front of the queue of points to be sorted.

[0027] Furthermore, the formation method described in step S5 includes several arrangements and combinations of primary gates.

[0028] Further, the method for calculating the average deadweight tonnage per lock in step S6 includes: based on the deadweight of each ship type in each lock arrangement within the same lock batch, combined with the total number of locks for each ship type in the predicted year, calculating the number of locks, deadweight, and the proportion of the number of locks required for each lock arrangement in the predicted year to the total number of locks required for each lock arrangement in the formation; the product of the proportion of each lock arrangement and the deadweight, and then summed, is the average deadweight tonnage per lock.

[0029] As the most common navigation structure in inland waterway transportation, locks have the functions of improving channel dimensions and water flow conditions. In most cases, the throughput capacity of a lock determines the transportation capacity of a waterway. Therefore, reasonably and accurately determining the throughput capacity of a lock is a key aspect of the design.

[0030] The advantages of this invention are that the principle it adopts is clear, the calculation process is simple, the results are accurate, and the efficiency is high, providing more accurate data support for the design of lock engineering. Attached Figure Description

[0031] Figure 1 This is a flowchart of the method described in this invention.

[0032] Figure 2 This is a flowchart of the two-dimensional bin packing algorithm described in this invention.

[0033] Figure 3 This is a schematic diagram of the two-dimensional bin packing algorithm described in this invention. Detailed Implementation

[0034] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0035] like Figure 1 As shown, the method for predicting the throughput capacity of a ship lock according to the present invention includes the following steps:

[0036] S1 provides the total freight volume, ship type, and proportion of freight volume carried by each ship type for the forecast year; as shown in Table 1:

[0037] Table 1:

[0038]

[0039] Among them, the number of times = cargo volume / deadweight of a single ship; cargo volume = total cargo volume * proportion of cargo handled.

[0040] S2 calculates the total number of ship voyages for each ship type in the predicted year; as shown in Table 1, the total number of voyages is 17,120.

[0041] S3, randomly combining vessel types and numbers into the same lock passage batch; for example, randomly combining 3 1+2×1000t convoys, 29 1000t vessels, 15 800t vessels, 16 1500t vessels, 4 70TEU vessels, and 4 50 TEU vessels, totaling 71 vessels, into the same lock passage batch, denoted as P1. Randomly combining 2 1+2×1000t convoys, 36 1000t vessels, 16 800t vessels, 18 1500t vessels, 6 70TEU vessels, and 4 50 TEU vessels, totaling 82 vessels, into the same lock passage batch, denoted as P2. Randomly combining 1 1+2×1000t convoy, 40 1000t vessels, 14 800t vessels, 18 1500t vessels, 6 70TEU vessels, and 4 50 TEU vessels, totaling 83 vessels, into the same lock passage batch, denoted as P3.

[0042] S4. Based on the lock length and width, and the ship length and width, a two-dimensional packing algorithm is used to determine the formation of ships within the same lock passage batch; the length and width statistics for each ship type are shown in Table 2.

[0043] Table 2:

[0044]

[0045] The gate chamber measures 280 meters in length and 34 meters in width.

[0046] like Figure 2 , Figure 3 As shown, the two-dimensional bin packing algorithm in step S4 is specifically as follows:

[0047] S4.1 Project the gate chamber horizontally as rectangle 1, take the lower left vertex of rectangle 1 as the origin, the length L1 direction as the X-axis, and the width W1 direction as the Y-axis to establish the gate chamber coordinate system; in this embodiment, the gate chamber is 280*34 meters long and wide, and the horizontal projection is rectangle 1 of 280*34 meters.

[0048] S4.2, Collect the length L2 and width W2 of the vessels in the same lock passage batch; Calculate the minimum number of vessels N that can be discharged from the lock chamber based on the length L2 and width W2 of the vessel with the largest length L2 and width W2.

[0049] Based on the length and width of each ship type listed in Table 2, it can be seen that the maximum length of the 1+2×1000 ship fleet is 135 meters, and the maximum width of the 70TEU fleet is 12.7 meters. Therefore, the minimum number of ships that can be accommodated in the lock chamber, N, can be calculated to be 2.

[0050] S4.3, when the number of vessels N1 in the same lock-passing batch is less than or equal to N, the vessels in the same lock-passing batch directly form one formation; that is, when N1 is less than or equal to 2, the vessels in the same lock-passing batch can all pass through the lock in one lock. In other words, the vessels in the same lock-passing batch form one formation.

[0051] In this embodiment, since the number of vessels in the same lock-passing batch P1, P2, and P3 is greater than 2, the vessels in the same lock-passing batch need to be divided into several lock sessions according to the following method. The vessels in each lock session need to be appropriately arranged to determine a lock arrangement combination C, ensuring that all vessels in the same lock-passing batch pass through the lock with the fewest possible lock sessions and the fewest lock opening and closing operations. Specifically:

[0052] S4.4 When the number N1 of ships in the same lock-passing batch is greater than N, N+1 ships are extracted according to the order of ship arrangement to form a pre-arranged queue A; for example, for ships in the same lock-passing batch P1, according to the order in which the ships arrive at the waiting area, 3 ships of 1+2×1000 are first selected to form a pre-arranged queue A.

[0053] S4.5, construct a queue of possible points with the coordinates of the origin of the gate chamber coordinate system as the first possible point; that is, coordinates (0,0) are the first possible point.

[0054] S4.6 Extract one ship B from the pre-arranged queue A, with a horizontal projection of rectangle 2 of length L2 and width W2; according to the arrangement order of the arrangement points in the arrangement point queue, place the lower left vertex of rectangle 2 at the arrangement point until an arrangement point is found that satisfies the condition that rectangle 1 completely contains rectangle 2 and there is no overlap between rectangles 2.

[0055] Extract one ship B from the pre-arranged queue A (1+2×1000 ships). Based on the statistics in Table 2, the length and width of the 1+2×1000 ship fleet are 135*10.8 meters. Project fleet B horizontally into rectangle 2 (135*10.8 meters). Place the bottom left vertex of rectangle 2 at coordinates (0,0). Then check if rectangle 1 completely contains rectangle 2, and if there is no overlap between rectangles 2. The specific judgment formula is:

[0056] (1)

[0057] Formula (1) is used to check whether rectangle 1 completely contains rectangle 2, where and The coordinates of the lower left vertex of the currently arranged vessel B placed in the lock chamber are the coordinates of the available points occupied by the currently arranged vessel B. and The length and width of ship B, which is currently being arranged; and Let be the length and width of the gate chamber. When all conditions of formula (1) are met, it can be determined that rectangle 1 completely contains rectangle 2.

[0058] (2)

[0059] Formula (2) is used to check for no overlap between rectangles 2. Wherein, and The coordinates of the lower left corner of the previous vessel B that is currently being arranged are located in the lock chamber. and The length and width of the previously arranged ship B.

[0060] S4.7, Delete the vertices that were occupied in step S4.6, and add the coordinates of the other vertices of rectangle 2 to the vertices queue in order;

[0061] Specifically, take the coordinates of the three vertices of rectangle 2 (excluding the lower left vertex) in the gate chamber coordinate system; compare any two coordinates, and place the one with the smaller x-coordinate value at the front of the queue of points that can be arranged; if the x-coordinates of the two coordinates are the same, then place the one with the smaller y-coordinate value at the front of the queue of points that can be arranged, and so on to form the queue of points that can be arranged.

[0062] Simultaneously, ship B is placed into the primary lock arrangement combination C;

[0063] If none of the available points in the available point queue can satisfy the condition that rectangle 1 completely contains rectangle 2 and there is no overlap between rectangles 2, then the vessel represented by rectangle 2 is removed from the pre-arrangement queue A, and a vessel smaller than that represented by rectangle 2 is selected from other vessels in P1 from the pre-arrangement queue A or the same lock-passing batch, and steps S4.6 and S4.7 are executed again.

[0064] S4.8, repeat S4.6 and S4.7 until the pre-sorted queue A is empty;

[0065] S4.9 If other vessels in the same lock-passing batch can still fit into rectangle 1, then execute steps S4.6 and S4.7 until no other vessels in the same lock-passing batch can fit into rectangle 1.

[0066] When the pre-arrangement queue A is empty, but there is still space in the lock chamber, one vessel B is sequentially extracted from other vessels in the same lock-passing batch P1, and it is virtually represented as rectangle 2. This vessel is then placed sequentially into the available position in the available position queue until an available position is found that satisfies the condition that rectangle 1 completely contains rectangle 2, and there is no overlap between rectangles 2. This continues until no other vessel in the same lock-passing batch P1 can fit into rectangle 1, indicating that the lock chamber is full. At this point, all vessels in the primary lock permutation combination C represent one primary lock permutation combination within the same lock-passing batch P1.

[0067] S4.10, repeat steps S4.4 to S4.9 until the number of ships N1 in the same lock-passing batch is 0; that is, the 71 ships in the same lock-passing batch P1 form a formation consisting of several permutations and combinations C described in the first lock.

[0068] S4.11 outputs several single-lock arrangements C as the formation method for vessels within the same lock-passing batch. Table 3 shows the formation methods for vessels within the same lock-passing batch P1:

[0069] Table 3

[0070]

[0071] S5, Repeat steps S3 and S4 to obtain several formation patterns for vessels within the same lock-passing batch; the formation patterns include several single-lock arrangements. Using the same method, randomly combined vessels in the same lock-passing batch P2 (82 vessels) and the same lock-passing batch P3 (83 vessels) can all form corresponding formation patterns. Table 4 shows the formation patterns of vessels within the same lock-passing batch P2:

[0072] Table 4

[0073]

[0074] Table 5 shows the formation of vessels within the same lock-passing batch P3:

[0075] Table 5

[0076]

[0077] S6, calculate the predicted annual freight volume according to the formation method, and the ship type of each ship in the formation method is equal to the average deadweight tonnage of a single lock run of the total number of ships;

[0078] Taking the formation of ships within the same lock-passing batch P1 as an example, the calculation process of the average deadweight tonnage per lock-pass is explained.

[0079] First, based on the predicted annual freight volume, ship type, annual freight volume ratio of each ship type, and annual number of ships of each ship type in Table 1, calculate the number of locks for each primary lock arrangement according to the formation of ships in P1.

[0080] Then, calculate the tonnage of each single-lock pass and the proportion of each single-lock pass to the total number of lock passes required for each single-lock pass in the formation of ships within P1. Next, multiply the proportion of each single-lock pass to the total number of lock passes by the tonnage of each single-lock pass, and sum all the results to obtain the predicted annual average tonnage of a single lock pass. The calculation results are shown in Table 6.

[0081] Table 6

[0082]

[0083] As shown in Table 1, the total cargo volume for the forecast year is 17 million tons, of which the 1+2×1000 fleet accounts for 10% of the total cargo volume, and it is estimated that there may be 850 1+2×1000 fleets in the forecast year. The number of other ship types can be calculated by analogy.

[0084] Based on the formation method of the same lock-passing batch P1, trial calculations show that the lock-passing combination "3 ships of 1 + 2 × 1000 tonnes + 3 ships of 1000 tonnes + 3 ships of 800 tonnes" requires 283 lock-passing times. This process can be repeated to determine the number of lock-passing times required for other lock-passing combinations. The total number of lock-passing times required for all lock-passing combinations is 1603, of which the lock-passing times required for the combination "3 ships of 1 + 2 × 1000 tonnes + 3 ships of 1000 tonnes + 3 ships of 800 tonnes" account for 283 / 1603 = 17.7% of the total.

[0085] Based on the maximum carrying capacity of a 1+2×1000 vessel convoy being 1000t, and the maximum carrying capacities of 1000t and 800t vessels being 1000t and 800t respectively, the single-lock passage tonnage of the combination "3 vessels in a 1+2×1000 convoy + 3 vessels in a 1000t convoy + 3 vessels in a 800t convoy" can be calculated to be 11400t. 11400 * 17.7% = 2014t. The sum of all single-lock passage combinations is 10619t, therefore the average single-lock passage tonnage is 10619t.

[0086] Because different vessels exist within the same lock passage batch, there are multiple formation methods, thus multiple predictions of the average deadweight tonnage per lock passage per year are possible.

[0087] S7, the maximum value among several single-lock average load tonnage is the predicted annual lock throughput capacity.

[0088] Based on the actual working conditions of inland waterway shipping, the predicted annual lock throughput capacity does not need to be very accurate. This value is mainly used as a reference for designing lock chambers. Therefore, the calculation results involved in the embodiments of this invention adopt rounding, approximation and other processing methods. The data is not 100% consistent, which is a normal phenomenon that can be accepted by those skilled in the art.

Claims

1. A method for predicting the throughput capacity of a ship lock, characterized in that: Includes the following steps: S1 provides the total freight volume, ship type, and the proportion of freight volume carried by each ship type for the forecast year. S2 calculates and predicts the total number of ship calls for each ship type in the current year; S3, random combination of ship type and number of ships in the same lock passage batch; S4, based on the lock length and width and the ship length and width, a two-dimensional packing algorithm is used to determine the formation of ships within the same lock passage batch; the two-dimensional packing algorithm in step S4 is specifically as follows: S4.1 Project the gate chamber horizontally as rectangle 1, take the lower left vertex of rectangle 1 as the origin, the length L1 direction as the X-axis, and the width W1 direction as the Y-axis to establish the gate chamber coordinate system; S4.2, Collect the length L2 and width W2 of the vessels in the same lock passage batch; Calculate the minimum number of vessels N that can be discharged from the lock chamber based on the length L2 and width W2 of the vessel with the largest length L2 and width W2. S4.3 When the number of ships N1 in the same lock-passing batch is less than or equal to N, the ships in the same lock-passing batch directly form one formation. S4.4 When the number N1 of ships in the same lock-passing batch is greater than N, N+1 ships are extracted according to the ship arrangement order to form a pre-arranged queue A; S4.5, using the coordinates of the origin of the gate chamber coordinate system as the first locating point, construct a locating point queue; S4.6 Extract one ship B from the pre-arranged queue A, with a horizontal projection of rectangle 2 of length L2 and width W2; according to the arrangement order of the arrangement points in the arrangement point queue, place the lower left vertex of rectangle 2 at the arrangement point until an arrangement point is found that satisfies the condition that rectangle 1 completely contains rectangle 2 and there is no overlap between rectangles 2. S4.7, Delete the available points occupied in step S4.6, and add the coordinates of the other vertices of rectangle 2 to the available point queue in order; put the ship B into the lock permutation combination C; S4.8, repeat S4.6 and S4.7 until the pre-sorted queue A is empty; S4.9 If other vessels in the same lock-passing batch can still fit into rectangle 1, then execute steps S4.6 and S4.7 until no other vessels in the same lock-passing batch can fit into rectangle 1. S4.10, repeat steps S4.4 to S4.9 until the number of vessels N1 in the same lock-passing batch is 0; S4.11, output the arrangement and combination C of several locks as the formation mode of ships in the same lock-passing batch; S5, repeat steps S3 and S4 to obtain the formation of several vessels in the same lock-passing batch; S6, calculate the predicted annual freight volume according to the formation method, and the ship type of each ship in the formation method is equal to the average deadweight tonnage of a single lock run of the total number of ships; S7, the maximum value among the several average load tonnages of a single lock operation is the predicted annual lock throughput capacity.

2. The method for predicting the throughput capacity of a ship lock according to claim 1, characterized in that: In step S4.6, if none of the available points in the available point queue can satisfy the condition that rectangle 1 completely contains rectangle 2 and there is no overlap between rectangles 2, then the vessel represented by rectangle 2 is removed from the pre-arrangement queue A, and a vessel smaller than rectangle 2 is selected from the pre-arrangement queue A or other vessels in the same lock-passing batch, and steps S4.6 and S4.7 are executed.

3. The method for predicting the throughput capacity of a ship lock according to claim 1, characterized in that: In step S4.7, adding the coordinates of the other vertices of rectangle 2 to the queue of points to be sorted in order includes: obtaining the coordinates of each vertex of rectangle 2 except the lower left vertex in the gate chamber coordinate system; comparing any two coordinates and placing the one with the smaller x-coordinate value at the front of the queue of points to be sorted; if the x-coordinates of the two coordinates are the same, then placing the one with the smaller y-coordinate value at the front of the queue of points to be sorted.

4. The method for predicting the throughput capacity of a ship lock according to claim 1, characterized in that: The formation method described in step S5 includes several arrangements and combinations of primary gates.

5. The method for predicting the throughput capacity of a ship lock according to claim 4, characterized in that: The method for calculating the average deadweight tonnage per lock in step S6 includes: based on the deadweight of each ship type in each lock arrangement within the same lock batch, and combined with the total number of locks for each ship type in the predicted year, calculating the number of locks, deadweight, and the proportion of the number of locks required for each lock arrangement in the predicted year to the total number of locks required for each lock arrangement in the formation; the product of the proportion of each lock arrangement and the deadweight, and then summed, is the average deadweight tonnage per lock.

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