A multi-path search method for urban rail transit network

Abstract

The application provides a kind of multi-path search method for urban rail transit network. Simplification processing of rail transit network topology is realized based on topology transformation to obtain a simplified topology network of urban rail transit. Different types of O-D pairs are divided according to the origin-destination (O-D) attribute, and a path matching type is designed. A K-shortest path algorithm is used to search for a simplified and effective path in the simplified topology network of urban rail transit based on the O-D pairs and the path matching type. A diameter mapping method is used for the simplified and effective path to obtain the mapping relationship between the stations in the simplified topology network of urban rail transit and the original urban rail transit network, thereby realizing a multi-path search method for large-scale urban rail transit network. The method can greatly improve the efficiency of the path search algorithm for urban rail transit network and provide support for passenger flow calculation and prediction of large-scale urban rail transit network.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of urban rail transit path search, and in particular to a multi-path search method for urban rail transit network. BACKGROUND

[0002] Urban rail transit gradually becomes an important mode of urban transportation with its advantages of convenience, punctuality, reliability and so on. With the continuous expansion of urban rail transit network, the number of lines and stations is increasing, which makes the network scale larger and larger, the network structure more and more complex, and the range of passenger travel path selection exponentially rising, which poses great challenges to its operation management. Under the condition of rapid development of information technology, fine management of urban rail transit system and provision of path planning and guidance for traveling passengers become an important issue of continuous concern for management departments.

[0003] Path search algorithm, especially multi-path search algorithm, has always been the core and key of urban rail transit network planning and operation management. At present, the K-short path search method in the prior art adopts the deviation path idea in the recursive method, and realizes it by adding additional nodes and corresponding links in the directed graph on the basis of the shortest path. In each iteration calculation, each station and link needs to be calculated repeatedly.

[0004] The disadvantages of the K-short path search method in the prior art include that the method has great calculation redundancy, and it is difficult to apply it to large-scale urban rail transit network. In addition, the calculation efficiency of the method is greatly affected by the scale of the network, and the complexity of the network topology structure will reduce the path search efficiency, and reducing the structural complexity of the urban rail transit network can greatly improve the efficiency of the path search. SUMMARY

[0005] The present application provides a multi-path search method for urban rail transit network to effectively improve the efficiency of the path search algorithm of urban rail transit network.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions.

[0007] A multi-path search method for urban rail transit network, comprising:

[0008] The urban rail transit network construction method based on topology transformation is adopted to realize the simplification processing of the original urban rail transit network topology structure, and obtain the simplified topology network of urban rail transit;

[0009] According to the origin-destination (O-D) attribute of a station, different types of O-D pairs are divided, path matching types are designed, and a K-shortest path algorithm is used to search for a simplified effective path in the simplified topology network of the urban rail transit by using the O-D pairs and the path matching types.

[0010] An arc mapping method is used for the simplified effective path to obtain a station mapping relationship between the simplified topology network of the urban rail transit and the original urban rail transit network, and a multi-path search method for a large-scale urban rail transit network is realized.

[0011] Preferably, the urban rail transit network construction method based on topology transformation is used to simplify the topology structure of the original urban rail transit network to obtain a simplified topology network of the urban rail transit, including:

[0012] For an original urban rail transit network G(V, E), where V and E represent a station set and a link set respectively, V = V1∪V2, V1 is a non-transfer station set, and V2 is a transfer station set, wherein the elements of the non-transfer station set are generally marked as V1', a topology network TN is constructed in a three-dimensional coordinate system (X, Y, Z) according to station longitude and latitude information (X, Y), Z = 0, and section connection information. asl An open rectangle U containing TN asl is established in the XOY plane, the open rectangle U and the topology network TN asl contained therein are projected along the Z-axis by one unit to form an open rectangle A, and the topology network TN asl is contained in the open rectangle A. The extreme values of the longitude and latitude coordinates of all non-transfer stations in the open rectangle A are extracted to form an open rectangle B, and the topology structure information of all non-transfer stations is contained in the open rectangle B.

[0013] According to the evolution rules of the nine-interchange model, the spatial topology relationship between the open rectangles A and B is continuously changed by moving the open rectangle B until the open rectangles A and B are completely separated, and then the removal of all non-transfer stations in the topology network TN asl in the open rectangle A is completed, and at the same time, the adjacent transfer stations of the non-transfer stations are recorded in a set , and the connection relationship of the non-transfer station is re-established to obtain a simplified topology network TN tsl only containing the transfer stations and corresponding connections.

[0014] According to the validity judgment condition of the section connection in the Dial algorithm, for a transfer station combination (T α , T β ) connected with O-D stations, a simplified topology network TN tslThe connections not satisfying the validity condition are deleted to obtain a hierarchical urban rail transit simplified topology network composed of transfer stations and valid connection relations

[0015] Preferably, the different types of O-D pairs are divided according to the origin-destination (O-D) attribute of the stations, path matching types are designed, a path search algorithm is used to search for a simplified valid path in the urban rail transit simplified topology network by using the O-D pairs and the path matching types, and the method comprises the following steps:

[0016] The O-D pairs in the urban rail transit network are divided into four types according to the station attribute as follows:

[0017] Non-transfer station-non-transfer station;

[0018] Non-transfer station-transfer station;

[0019] Transfer station-non-transfer station;

[0020] Transfer station-transfer station;

[0021] The following parameters are defined:

[0022] v o / v d : departure station / arrival station;

[0023] OList: v o is a non-transfer station, and a set composed of transfer stations adjacent to v o , and the elements are:

[0024] DList: v d is a non-transfer station, and a set composed of transfer stations adjacent to v d , and the elements are:

[0025] For the above four different types of O-D pairs, four corresponding path search mechanisms are designed, and a K-path algorithm is called to obtain a simplified valid path between O-D in the urban rail transit simplified topology network.

[0026] Preferably, for the above four different types of O-D pairs, four corresponding path search mechanisms are designed, and a K-path algorithm is called to obtain a simplified valid path between O-D in the urban rail transit simplified topology network, and the method comprises the following steps:

[0027] (1) v o is a non-transfer station, v d is a non-transfer station ​​

[0028] Confirm v o and v d By calling Collection in The system identifies the station elements in both the OList and DList. These station elements are then cross-combined to obtain transfer station combinations. Finally, valid routes are filtered to obtain the final result. Using the K-shortest path algorithm in Search the internal path to get v o -v d A streamlined and effective path between them;

[0029] (2)v o Is it a transfer station, v d It is a transfer station

[0030] exist In the middle, v d It is a transfer station, through Specific elements contained in OList, if OD is not on a loop and OList does not contain v d The K-shortest path algorithm is used to search for a simplified and efficient path to obtain v. o -v d A streamlined and effective path between them;

[0031] (3)v o It's a transfer station, v d Is it a transfer station?

[0032] v d Is it a transfer station or not? Call To determine the elements contained in the DList, if the OD is not on the cycle and the DList does not contain v o Then, the K-shortest path algorithm is used to search for v. o -v d A streamlined and effective path between them;

[0033] (4)v o It's a transfer station, v d It is a transfer station

[0034] v o With v d If a group of transfer stations is formed, then the K-shortest path algorithm can be used to... Internal search yields v o -v d A streamlined and effective path between them.

[0035] Preferably, the method of using a path mapping approach for the simplified effective path to obtain the station mapping relationship between the simplified urban rail transit topology network and the original urban rail transit network, thereby realizing a multi-path search method for large-scale urban rail transit networks, includes:

[0036] Step 1: The transfer stations on each streamlined and efficient route are projected onto the TN after path mapping. asl ;

[0037] Step 2: Pass through the beginning and end of each streamlined and effective path. Link v respectively o ,v d In addition, through By restoring the non-transfer stations along the route, the complete K-shortest path can be obtained;

[0038] Step 3: Eliminate K-shortest paths with loops to obtain the path for v. o ,v d The final set of K-shortest paths;

[0039] TN asl To establish the original topology network that includes all stations and segment connections, With TN asl The mapping relationship between them will The transfer stations in the TN are projected onto the TN. asl middle,

[0040] In addition, non-transfer stations and OD stations will be added, and the specific methods are as follows:

[0041] (1) Based on the principle of path mapping, the simplified topology of urban rail transit is represented in the coordinate system (X,Y,Z). Transfer stations within (x) i ,y i ,η) and the topology TN asl Transfer stations on the road (x) i ,y i The topological network is associated with i = 1, 2, ..., n, i = 0, i = 1, 2, ..., n. TN asl There is an η-unit distance between them along the Z-axis;

[0042] (2) For each transfer station (x) on each streamlined and efficient route i ,y i Construct the unit circle S, η). i Different S i Placed in different coordinate systems (X′) i ,Y′ i ,Z′ i In different coordinate systems (X′) i,Y′ i ,Z′ i The origin O of the network is located at the network. and TN asl On the midline between the planes, each topological network All transfer stations in the S area will be located in S i There is a coordinate system with the following characteristics:

[0043]

[0044] Through the path mapping variant r:S i →S i For any have Thus, the network The transfer stations within the TN are then inversely mapped to the TN network. asl Above, that is:

[0045]

[0046] Through the above variant of the path mapping, the inverse mapping of transfer stations within the hierarchically simplified urban rail transit topology network G1(V',E') is obtained. G1(V',E') is derived from the simplified urban rail transit topology network. Together with the open rectangle B that only contains non-transfer stations, it forms a whole.

[0047] As can be seen from the technical solutions provided by the embodiments of the present invention above, the method of the embodiments of the present invention can greatly improve the efficiency of urban rail transit network path search algorithms and provide support for passenger flow calculation and prediction of large-scale urban rail transit networks.

[0048] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and will become apparent from the description or may be learned by practice of the invention. Attached Figure Description

[0049] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 A flowchart illustrating a resource management method in a multimedia communication system provided by an embodiment of the present invention;

[0051] Figure 2 This invention provides an embodiment of an OList and a DList of station elements and a simplified topology network for urban rail transit. Schematic diagram.

[0052] Figure 3 This is a schematic diagram illustrating the inverse mapping of transfer stations within a hierarchically simplified urban rail transit topology network G1(V',E') provided by an embodiment of the present invention.

[0053] Figure 4 A schematic diagram of the Beijing urban rail transit network provided as an embodiment of the present invention;

[0054] Figure 5 is a schematic diagram of the changes in the topological relationship of an object set during the extraction of rail transit network stations according to an embodiment of the present invention;

[0055] Figure 6 A T provided for embodiments of the present invention α＝1 (L10, Princess Tomb, Down) → T β＝1 Schematic diagram of the effective link range of (L5, Dongdan, Up);

[0056] Figure 7 A violin diagram showing the running times of four K-shortest path algorithms provided in this embodiment of the invention.

[0057] Figure 8 This is a box plot diagram illustrating the number of sites visited by four K-shortest path algorithms, provided as an embodiment of the present invention. Detailed Implementation

[0058] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0059] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. It should be understood that when we say an element is “connected” or “coupled” to another element, it can be directly connected or coupled to the other element, or there may be intermediate elements. Furthermore, “connected” or “coupled” as used herein can include wireless connections or couplings. The term “and / or” as used herein includes any and all combinations of one or more of the associated listed items.

[0060] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0061] To facilitate understanding of the embodiments of the present invention, the following will provide further explanation and description with reference to the accompanying drawings and several specific embodiments. These embodiments do not constitute a limitation on the embodiments of the present invention.

[0062] The path search method for large-scale urban rail transit networks provided in this invention reduces redundant stations and links in the urban rail transit network while ensuring that the simplified network has the same topological relationship as the original network during the path search process. Furthermore, paths searched in the simplified network can be mapped to paths in the original network.

[0063] A flowchart of a multi-path search method for large-scale urban rail transit networks provided by an embodiment of the present invention is shown below. Figure 1 As shown, the processing steps include the following:

[0064] Step S10: The original urban rail transit network topology is simplified using a topology transformation-based urban rail transit network construction method, resulting in a hierarchical simplified urban rail transit topology network G1(V′,E′). The specific method is as follows:

[0065] (1) For the urban rail transit network G(V,E), where V and E represent the set of stations and the set of links, respectively. V = V1∪V2, where V1 is the set of non-transfer stations and V2 is the set of transfer stations, and the elements of the non-transfer station set are generally labeled as V1'. First, in the three-dimensional coordinate system (X,Y,Z), the topology network TN is constructed based on the station latitude and longitude information (X,Y), Z=0 and the segment connection information. asl Establish a TN-containing structure in the XOY plane. asl Draw an open rectangle U; then translate it along the Z-axis. A unit projected open rectangle U and its contained topology TN asl This forms an open rectangle A, which also contains the rail transit topology network TN. asl Next, extract the extreme values ​​of latitude and longitude coordinates of all non-transfer stations within A to form an open rectangle B. The open rectangle B contains only the topological information of all non-transfer stations.

[0066] (2) Based on the evolution rules of the nine-way model, by moving open rectangle B, the spatial topological relationship between open rectangle A and B is continuously changed until open rectangle A and B are completely separated, thereby completing the topological network TN within open rectangle A. asl All non-transfer stations are removed from the set. Each time a non-transfer station is removed, its adjacent transfer stations need to be recorded in the set. In this process, the connection relationships of the non-transfer station are re-established. For example, there is a non-transfer station S2 in the Up direction of line L2, and the adjacent transfer stations S1 and S3 are S2. When the non-transfer station S2 is moved out of the open rectangle A, the corresponding set... It is denoted as: {(L2,S2,Up)-(L2,S1,Up),(L2,S3,Up)}. Therefore, a simplified topology network TN consisting only of transfer stations and their corresponding connections can be obtained. tsl .

[0067] (3) Based on the validity criteria for segment connections in the Dial algorithm, for transfer station combinations (T) connected to OD stations... α ,T β In simplified topology networks TN tsl Remove connections that do not meet the validity criteria to obtain a simplified urban rail transit topology network consisting only of transfer stations and valid connections.

[0068] Through the above operations, the original topology network TN, which includes all stations and segment connections, is formed. asl A simplified urban rail transit topology network consisting of transfer stations and effective links. Together with the open rectangle B containing only non-transfer stations, they constitute the hierarchical urban rail transit topology network system G1(V′,E′).

[0069] Step S20: Simplify the topology network of urban rail transit according to the OD station type. Path search is performed.

[0070] First, based on station attributes, OD (Origin to Destination) pairs in urban rail transit networks are divided into the following four types:

[0071] • Non-transfer station - non-transfer station;

[0072] • Non-transfer station - transfer station;

[0073] • Transfer station - non-transfer station;

[0074] • Transfer stations - Transfer stations.

[0075] Define the following parameters:

[0076] ·v o / v d Departure station / Arrival station;

[0077] ·OList:v o When it is not a transfer station, with v o The set of adjacent transfer stations, whose elements are

[0078] ·DList: v d When it is not a transfer station, with v d The set of adjacent transfer stations, whose elements are

[0079] For the four different types of OD pairs mentioned above, four corresponding path search mechanisms are designed, and the K-path algorithm is called in... The simplified and efficient paths between ODs are obtained. It should be noted that there are special cases, such as v... o With v d If all routes belong to the same loop line, then all paths except the shortest path need to be obtained through a search mechanism; otherwise, all simplified and effective paths can be obtained directly through a path search mechanism; if OList and DList contain the same transfer stations, then v o With v d The shortest, simplified, and efficient path between them can be obtained through the K-shortest path algorithm, while the remaining paths still need to be obtained through a path search mechanism.

[0080] The specific path search mechanism is as follows:

[0081] (1)v o Is it a transfer station, v d Is it a transfer station?

[0082] Confirm v o and v d OList and DList site elements are accessed through calls Collection in Internal determination. Figure 2 This invention provides an embodiment of an OList and a DList of station elements and a simplified topology network for urban rail transit. Schematic diagram, in Figure 2 In the diagram, J′ and G′ represent v o v d This is recorded when the site is retrieved. Therefore:

[0083] List J' {(L1,J′,Up)-(L1,N′,Up)},

[0084] List G' {(L2,G′,Down)-(L2,K′,Down),(L2,M′,Down)},

[0085] Therefore, T α＝1 It is N′,T β＝1 It is K′,T β＝2 It is M′. After cross-combining the station elements of OList and DList to obtain the transfer station combinations, the valid paths are then filtered to obtain... like Figure 1 As shown, the path is obtained after filtering the transfer station combination (N', K'). Then, using the K-shortest path algorithm in The internal search path is denoted as a concise and efficient path.

[0086] (2)v o Is it a transfer station, v d It is a transfer station

[0087] exist In the middle, v d It's a transfer station. (Through...) Specify the elements contained in OList. If OD is not on a loop and OList does not contain v d The K-shortest path algorithm is used to search for a simplified and effective path, and other cases are handled specially.

[0088] (3)v o It's a transfer station, v d Is it a transfer station?

[0089] Because of v d Is it a transfer station or not? Call To determine the elements contained in the DList. Unlike case 2), v o It is a transfer station. Similarly, if the OD is not on the loop and the DList does not contain v o If the K-shortest path algorithm is used to search for a simplified and effective path, other cases will be handled specially.

[0090] (4)v o It's a transfer station, v d It is a transfer station

[0091] v o With v d This constitutes a group of transfer stations, in You can directly search for streamlined and efficient routes. Other transfer station combinations can be found based on v. o With v d Reverse search Once confirmed, the K-shortest path algorithm is invoked to search for other simplified and effective paths.

[0092] Step S30: Determine the original network TN based on the path mapping relationship in the hierarchical urban rail transit topology network G1(V′,E′). asl The set of valid paths in.

[0093] Based on the simplified topology network of urban rail transit The valid paths found in the search can be used to obtain the original network TN based on the network topology mapping relationship. asl The valid path in the code, and the specific steps are as follows:

[0094] Step 1: The transfer stations on each streamlined and efficient route are projected onto the TN after path mapping. asl ;

[0095] Step 2: Pass through the beginning and end of each streamlined and effective path. Link v respectively o ,v d In addition, through By restoring the non-transfer stations along the route, the complete K-shortest path can be obtained;

[0096] Step 3: Eliminate K-shortest paths with loops to obtain the path for v. o ,v d The final set of K-shortest paths.

[0097] Establish With TN asl The mapping relationship between them will The transfer stations in the TN are projected onto the TN. asl In addition, non-transfer stations and OD stations will be added. The specific method is as follows:

[0098] (1) Based on the principle of path mapping, the simplified topology of urban rail transit is represented in the coordinate system (X,Y,Z). Transfer stations within (x) i ,y i ,η) and the topology TN asl Transfer stations on the road (x) i ,y i The topological network is associated with i = 1, 2, ..., n, i = 0, i = 1, 2, ..., n. TN asl There is a distance of η units between them along the Z-axis.

[0099] (2) For each transfer station (x) on each streamlined and efficient route i ,y i ,η), construct the unit circle Si, different S i Placed in different coordinate systems (X′)i ,Y′ i ,Z′ i In different coordinate systems (X′) i ,Y′ i ,Z′ i The origin O of the network is located at the network. and TN asl On the midline between the planes they lie on. Thus, each topological network... All transfer stations in the S area will be located in S i There is a coordinate system with the following characteristics:

[0100]

[0101] Through the path mapping variant r:S i →S i For any have Thus, the network The transfer stations within the TN are then inversely mapped to the TN network. asl Above, that is:

[0102]

[0103] Through the above variants of the path mapping, we obtain the following: Figure 3 The diagram illustrates the inverse mapping of transfer stations within a hierarchically simplified urban rail transit topology network G1(V',E').

[0104] Example 1

[0105] This invention simplifies urban rail transit networks by hierarchically transforming topology, thus constructing a hierarchical network. Furthermore, it derives the hierarchical topology network based on the principle of path mapping. With TN asl The mapping relationship between them is established. Finally, four matching mechanisms are designed for different OD combination types to efficiently complete the track network path search process.

[0106] by Figure 4 Taking the Beijing rail network as an example, a specific instance is provided for illustration. The rail network includes 42 transfer stations, 85 non-transfer stations, and 12 lines. To demonstrate the effectiveness and efficiency of the multi-path search method for large-scale urban rail transit networks, three other K-shortest path algorithms can be selected as comparison algorithms for path search within the original rail topology network.

[0107] First, given OD(L10, Lotus Bridge, Down) → (L5, Dengshikou, Up), the target is to search for the K-shortest path (K=3), and the effectiveness of the multi-path search method for large-scale urban rail transit networks is verified.

[0108] (1) Constructing the track network topology TN asl By establishing a projection mapping to remove all non-transfer stations, the first layer of simplification of the track topology network is achieved, resulting in the simplified topology network TN. tsl Figure 5 is a schematic diagram of the changes in the topological relationship of the object set during the extraction of a rail transit network station according to an embodiment of the present invention. Figure 5 describes three states during the station extraction process. Figure 5(a) shows the initial topological state of constructing open rectangle A. Figure 5(b) describes the "intersecting" topological relationship between open rectangle A and open rectangle B at a certain moment during the station extraction process. Figure 5(c) shows the "separated" topological relationship between open rectangle A and open rectangle B after the station extraction is completed.

[0109] (2) Based on Find the transfer stations adjacent to the OD:

[0110] List 灯市口 {(L5,Dengshikou,Up)-(L5,Dongdan,Up),(L5,Dongsi,Up)};

[0111] List 莲花桥 {(L10, Lotus Bridge, Down)-(L10, Princess Tomb, Down),(L10, Liuli Bridge, Down)}.

[0112] Therefore, since ODs are all non-transfer stations, the element T contained in OList is called. α＝1 It is (L10, Princess Tomb, Down), T α＝2 It is (L10, Liuliqiao, Down). The DList contains element T. β＝1 It is (L5, Dongsi, Up), T β＝2 It is (L5, Dongdan, Up).

[0113] (3) Combine the transfer stations contained in OList and DList one by one to obtain four pairs of transfer station combinations (T α ,T β ):

[0114] (L10, Gongzhufen, Down) → (L5, Dongdan, Up);

[0115] (L10, Gongzhufen, Down) → (L5, Dongsi, Up);

[0116] (L10, Liuliqiao, Down) → (L5, Dongdan, Up);

[0117] (L10, Liuliqiao, Down) → (L5, Dongsi, Up).

[0118] For each pair of transfer station combinations (T) α ,Tβ ) Path selection is performed to obtain a simplified urban rail transit topology network one by one. With T α＝1 (L10, Princess Tomb, Down) → T β＝1 (L5, Dongdan, Up) as an example Figure 6 A T provided for embodiments of the present invention α＝1 (L10, Princess Tomb, Down) → T β＝1 Schematic diagram of the effective link range of (L5, Dongdan, Up).

[0119] Similarly, for the other three pairs of transfer station combinations, the simplified topology network TN is used. tsl Based on this, the effective path range is filtered.

[0120] (4) For each pair of transfer stations, in the simplified topology network of urban rail transit The internal call uses the K-short-circuit algorithm to find a simplified and efficient path. For example, T α＝1 (L10, Princess Tomb, Down) → T β＝1 The streamlined and efficient paths (K=3) between (L5, Dongdan, Up) are summarized in Table 1.

[0121] Table 1 shows the valid paths between (L10, Gongzhufen, Down) and (L5, Dongdan, Up).

[0122]

[0123] Similarly, the simplified and efficient paths (K=3) between the other three pairs of transfer station combinations can also be obtained.

[0124] (5) The streamlined and efficient path (K=3) between each pair of transfer stations is projected onto TN through path mapping. asl .according to Link v0 and v respectively d In addition to non-transfer stations, each streamlined and effective path was completed. Paths with loops were eliminated, and the effective paths with the lowest travel costs were selected, ultimately obtaining the K-shortest path (K=3) between a given OD(L10, Lotus Bridge, Down) → (L5, Dengshikou, Up). The results are summarized in Table 2.

[0125] Table 2 shows the K-shortest path (K=3) between (L10, Lotus Bridge, Down) and (L5, Dengshikou, Up).

[0126]

[0127] Below, we will verify the efficiency of the multi-path search method for large-scale urban rail transit networks from different perspectives.

[0128] (1) Comparison of running times: Ten groups containing different numbers of OD pairs were set up, and the running times of SP+Yen's_R and Yen's algorithm, DFS algorithm and KSP-LPA* algorithm for searching K-shortest paths (K=3) were compared. Figure 7 The diagram shows the running times of four K-shortest path algorithms provided in this embodiment of the invention. As shown in the violin diagram #1, they are all at the top of each group, thus proving that Yen's algorithm performs the worst among the four algorithms. This is because Yen's algorithm needs to traverse all stations in each path search, and the station size is large, leading to a continuously increasing computational load. The diagram #3 shows that KSP-LPA* is slightly inferior to SP+Yen's_R, thanks to its reuse of the shortest path tree when calculating the deviation path. Compared to Yen's algorithm, the DFS algorithm improves the search speed, but its search speed is still worse than the other two algorithms. Taking 80 O-Ds as an example, the running time of Yen's algorithm is 5.5 times that of SP+Yen's_R, with average values ​​of 8.29E+04ms and 1.28E+04ms, respectively.

[0129] It can be seen that the multi-path search algorithm for large-scale urban rail transit networks has a significant advantage over the reference algorithm because its density distribution is more concentrated. Conversely, the density distribution of the reference algorithm is discrete. That is, this algorithm has the best robustness to actual operation. The computational performance of several algorithms with 20 O-Ds is observed. SP+Yen's_R has the smallest interquartile range (IQR) in its group, while Yen's algorithm has the largest IQR. KSP-LPA* and DFS are both greater than the proposed algorithm. Similar relationships exist among the IQRs in other groups. Along the X-axis, the running time of SP+Yen's_R increases slowly with the number of ODs, but other algorithms are significantly affected. This experiment demonstrates that the proposed SP+Yen's_R is an efficient K-shortest path search method.

[0130] (2) Comparison of the number of accessed sites: All four K-shortest path search algorithms were run 20 times, with K set to 3 and the number of OD pairs taking three different values ​​(3, 5 and 8). Figure 8 This is a box plot diagram illustrating the number of sites visited by four K-shortest path algorithms, provided as an embodiment of the present invention.

[0131] In the box line Figure 8Among the results, SP+Yen's_R has the lowest average number of stations visited because it visits fewer stations than other algorithms after simplifying the track topology network through hierarchical methods. This result indicates the difference in runtime to some extent. Specifically, Yen's algorithm visits twice as many stations as SP+Yen's_R. For DFS, the number of stations visited is slightly lower than Yen's algorithm, but significantly higher than the algorithm presented in this paper. KSP-LPA* reduces computation by ignoring the entire shortest path tree in each offset path calculation, but it is still inferior to the algorithm presented in this paper.

[0132] In summary, the compression operation in the multi-path search method for urban rail transit networks provided by this invention is an effective method to avoid redundant path searching. Furthermore, the four designed matching mechanisms accelerate the path search process.

[0133] This invention provides a method for multi-path search in large-scale urban rail transit networks, which can efficiently and rationally find multiple effective paths for passenger travel in a large-scale and complex urban rail transit network.

[0134] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of one embodiment, and the modules or processes shown in the drawings are not necessarily essential for implementing the present invention.

[0135] As can be seen from the above description of the embodiments, those skilled in the art can clearly understand that the present invention can be implemented by means of software plus necessary general-purpose hardware platforms. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in various embodiments or some parts of the embodiments of the present invention.

[0136] The various embodiments in this specification are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for apparatus or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The apparatus and system embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0137] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A multi-path search method for urban rail transit networks, characterized in that, include: A method for constructing urban rail transit networks based on topology transformation is used to simplify the original urban rail transit network topology, resulting in a simplified urban rail transit topology network. Based on the origin-to-destination (OD) attributes of the stations, different types of OD pairs are defined, path matching types are designed, and the OD pairs and path matching types are used to... The short-circuit algorithm searches for a simplified and efficient path within the simplified topology network of the urban rail transit system. A path mapping method is used for the simplified and effective paths to obtain the station mapping relationship between the simplified urban rail transit topology network and the original urban rail transit network, thereby realizing a multi-path search method for large-scale urban rail transit networks. The process of classifying different types of OD pairs based on the origin-to-destination OD attributes of stations, designing path matching types, and using the OD pairs and path matching types to employ a path search algorithm to search for simplified and effective paths within the simplified topology network of the urban rail transit system includes: Based on station attributes, OD pairs in urban rail transit networks are classified into the following four types: Non-transfer station - Non-transfer station; Non-transfer station - transfer station; Transfer station - non-transfer station; Transfer stations - transfer stations; Define the following parameters: Departure station / Arrival station; : When it is not a transfer station, with The set of adjacent transfer stations consists of the following elements: , ∈[1,2], ∈ +; : When it is not a transfer station, with The set of adjacent transfer stations consists of the following elements: , ∈[1,2], ∈ +; For the four different types of OD pairs mentioned above, four corresponding path search mechanisms are designed and called... Path algorithms in urban rail transit simplified topology networks The simplified and efficient path between ODs is obtained internally; The method described above employs a path mapping approach for the simplified and effective paths to obtain the station mapping relationship between the simplified urban rail transit topology network and the original urban rail transit network, thereby realizing a multi-path search method for large-scale urban rail transit networks, including: Step 1: The transfer stations on each streamlined and efficient route are projected onto the corresponding routes through path mapping. ; Step 2: Pass through the beginning and end of each streamlined and effective path. Links respectively In addition, through The non-transfer stations along the restoration route are restored to obtain the complete route. Shortest path; Step 3: Eliminate items with loops Shortest path, get targeted The final Shortest path set; To establish the original topology network that includes all stations and segment connections, and The mapping relationship between them will The transfer stations in the middle are projected to middle, In addition, non-transfer stations and OD stations will be added, and the specific methods are as follows: (1) According to the principle of diametrical mapping, in the coordinate system In this context, the urban rail transit network topology will be simplified. internal transfer stations With topology network Transfer stations on , Related, topology network , Between along Shaft has Unit distance; (2) For each transfer station on each streamlined and efficient route Construct a unit circle Different Placed in different coordinate systems In different coordinate systems The origin In the network and On the midline between the planes, each topology network All the transfer stations in the middle will be in There is a coordinate system with the following characteristics: Through the variant of the path mapping For any have Thus, the network The transfer stations within are inversely mapped to Above, that is: Through the above variants of path mapping, a simplified urban rail transit topology network in a hierarchical manner is obtained. Internally, the inverse mapping of transfer stations is implemented. Simplified topology network by urban rail transit And open rectangles that only contain non-transfer stations Together they constitute.

2. The method according to claim 1, characterized in that, The method for constructing urban rail transit networks based on topology transformation simplifies the original urban rail transit network topology, resulting in a simplified urban rail transit topology network, including: For the original urban rail transit network ,in and These represent the set of sites and the set of links, respectively. , A collection of non-transfer stations. It is a set of transfer stations, where the elements of the non-transfer station set are generally tagged as In a three-dimensional coordinate system Based on the station's latitude and longitude information , And segment connection information to construct the topology network ,exist Constructing within a plane Open rectangle ,along Axis translation , ∈ + units projected into a rectangle and its included topology network , forming an open rectangle Open rectangle It contains a rail transit topology network. Extract the open rectangle The open rectangle formed by the extreme values ​​of latitude and longitude coordinates of all non-transfer stations within the area. Open rectangle It contains only the topology information of all non-transfer stations; Based on the evolution rules of the nine-intersection model, by moving the open rectangle Continuously change the open rectangle and Spatial topological relationships, up to the open rectangle and Complete separation, thus completing the rectangular opening. Inner topology network All non-transfer stations are removed from the network. Each time a non-transfer station is removed, the adjacent transfer stations are recorded in a set. In this process, the connection relationships of the non-transfer station are re-established, resulting in a simplified topology network consisting only of transfer stations and their corresponding connections. ; Based on the validity criteria for segment connections in the Dial algorithm, this applies to transfer station combinations connected to OD stations. In simplifying the topology network Remove connections that do not meet the validity criteria to obtain a simplified urban rail transit topology network consisting only of transfer stations and valid connections. .

3. The method according to claim 1, characterized in that, The above-described four different types of OD pairs are designed with four corresponding path search mechanisms, which are called... Path algorithms in urban rail transit simplified topology networks The simplified and efficient paths between ODs are obtained internally, including: (1) Is it a transfer station? Is it a transfer station? confirm as well as By calling Collection in Internal determination as well as Site elements, will and After cross-combining the station elements to obtain the transfer station combinations, the valid routes are then filtered to obtain the final result. ,use Shortest path algorithm in Internal search path, obtained - A streamlined and effective path between them; (2) Is it a transfer station? It is a transfer station exist middle, It is a transfer station, through clear The included elements, if the OD is not on the loop and Not included ,use The shortest path algorithm searches for a simplified and efficient path, resulting in... - A streamlined and effective path between them; (3) It is a transfer station. Is it a transfer station? Is it a transfer station or not? Call To determine The included elements, if the OD is not on the loop and Not included Then utilize Shortest path algorithm search results - A streamlined and effective path between them; (4) It is a transfer station. It is a transfer station and To form a group of transfer stations, then utilize Shortest path algorithm in Internal search results - A streamlined and effective path between them.

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