KR102185690B1 - Method of deciding one-way roads based on 2-SAT in smart cities - Google Patents

Abstract

Disclosed are a method and device for planning a road network. According to one embodiment of the present invention, the device for planning a road network may receive road information on roads included in a target road network and driving route information on driving paths of vehicles traveling on the target road network, assign an identifier based on a boolean variable, which distinguishes a forward direction and an opposite direction to each of the roads, express the driving routes included in the driving route information as CNF of 2-SAT using the boolean variable, acquire a solution of the CNF using SCC, and determine a direction for one-way traffic for at least some roads based on the acquired solution of the CNF.

Description

Method of deciding one-way roads based on 2-SAT in smart cities}

The following embodiments relate to a method for determining one-way road network traffic using 2-SAT in a smart city.

Smart cities apply intelligent computer algorithms to urban planning to improve efficient resource management and convenience in life. Traffic is an important issue in smart cities, and big data related to traffic is available, and efficient road network operation plans based on this have various effects, such as reducing travel time and waste of fuel. In order to facilitate traffic, a one-way road system can be introduced, which can be mainly used in a grid type road network. In one-way traffic, it is possible to set the direction of travel alternately for each horizontal or vertical road in order for users to easily find the way, but considering the situation in which most drivers are familiar with the use of navigation and road structure, traffic flows smoothly. You can also set the direction of progress for the purpose of Moreover, since there are flows that occupy a large part of the traffic flow in the road network, it is desirable to allow them to easily move through a one-way traffic network.

According to an embodiment, a method of operating a road network planning apparatus includes: receiving road information about roads included in a target road network, and driving route information about driving paths of vehicles traveling on the target road network; Allocating to each of the roads an identifier based on a boolean variable for distinguishing a forward direction and an opposite direction; Expressing the driving paths included in the driving path information in a Conjunctive Normal Form (CNF) of 2-SAT (satisfiability) by using the Boolean variable; Obtaining a solution of the CNF using a Strongly Connected Component (SCC); And determining a direction for one-way traffic with respect to at least some of the roads, based on the obtained solution of the CNF.

The target road network is a grid type road network including horizontal roads and vertical roads, and the step of allocating the identifier has a true value for a first horizontal direction to a first horizontal road among the horizontal roads, and the first Allocating a first identifier corresponding to a first boolean variable having a false value with respect to a second horizontal direction opposite to the horizontal direction; And a second boolean variable corresponding to a first vertical road among the vertical roads, which has a true value with respect to a first vertical direction and a false value with respect to a second vertical direction opposite to the first vertical direction. 2 It may include the step of allocating an identifier.

The step of expressing the driving paths in the CNF may include determining a path type of a first driving path among the driving paths; Selecting a first type of logical expression corresponding to the route type of the first driving route from among a plurality of logical expressions each having a predefined format for various route types; Selecting a first clause corresponding to the logical expression of the first type from among clauses pre-normalized corresponding to the plurality of logical expressions; And expressing at least a part of the CNF by substituting the first identifier of the first driving route in the first section.

The various route types include a first type traveling straight in a horizontal direction, a second type traveling straight in a vertical direction, a third type traveling in a vertical direction after traveling in a horizontal direction, and a horizontal direction after traveling in a vertical direction. It may include a fourth type that rotates and travels.

According to an embodiment, the road network planning apparatus includes a processor; And a memory including instructions executable by the processor, and when the instructions are executed by the processor, the processor includes road information on roads included in the target road network, and driving paths of vehicles traveling on the target road network. Receiving driving route information for, assigning an identifier based on a boolean variable for distinguishing the forward direction and the opposite direction to each of the roads, and using the Boolean variable to 2-SAT the driving routes included in the driving route information Expressed in Conjunctive Normal Form (CNF) of (satisfiability), obtained the solution of the CNF using Strongly Connected Component (SCC), and based on the solution of the obtained CNF, at least some of the roads To determine the direction for one-way traffic.

1 is a view showing the operation of a road network planning apparatus according to an embodiment.
2 is a diagram showing a target road network defined according to an embodiment.
3 to 6 are diagrams showing path types according to an embodiment.
7 is a diagram illustrating a process of obtaining a CNF solution using SCC according to an embodiment.
8 is a flow chart showing a road network planning method according to an embodiment.
9 is a block diagram showing an apparatus for planning a road network according to an embodiment.

Specific structural or functional descriptions of the embodiments according to the concept of the present invention disclosed in this specification are exemplified only for the purpose of describing the embodiments according to the concept of the present invention, and embodiments according to the concept of the present invention They may be implemented in various forms and are not limited to the embodiments described herein.

Since the embodiments according to the concept of the present invention can apply various changes and have various forms, the embodiments will be illustrated in the drawings and described in detail herein. However, this is not intended to limit the embodiments according to the concept of the present invention to specific disclosed forms, and includes changes, equivalents, or substitutes included in the spirit and scope of the present invention.

Terms such as first or second may be used to describe various elements, but the elements should not be limited by the terms. The above terms are only for the purpose of distinguishing one component from other components, for example, without departing from the scope of rights according to the concept of the present invention, the first component may be named as the second component, Similarly, the second component may also be referred to as a first component.

When a component is referred to as being “connected” or “connected” to another component, it is understood that it may be directly connected or connected to the other component, but other components may exist in the middle. Should be. On the other hand, when a component is referred to as being “directly connected” or “directly connected” to another component, it should be understood that there is no other component in the middle. Expressions that describe the relationship between components, for example, “between” and “just between” or “directly adjacent to” should be interpreted as well.

The terms used in the present specification are only used to describe specific embodiments and are not intended to limit the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In the present specification, terms such as "comprise" or "have" are intended to designate that the specified features, numbers, steps, actions, components, parts, or combinations thereof exist, but one or more other features or numbers, It is to be understood that the presence or addition of steps, actions, components, parts or combinations thereof does not preclude the possibility of preliminary exclusion.

Unless otherwise defined, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by a person of ordinary skill in the art to which the present invention belongs. Terms as defined in a commonly used dictionary should be interpreted as having a meaning consistent with the meaning in the context of the related technology, and should not be interpreted as an ideal or excessively formal meaning unless explicitly defined in this specification. Does not.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. However, the scope of the patent application is not limited or limited by these embodiments. The same reference numerals in each drawing indicate the same members.

1 is a diagram illustrating an operation of a road network planning apparatus according to an embodiment. Smart cities apply intelligent computer algorithms to urban planning to improve efficient resource management and convenience in life. Traffic is an important issue in smart cities, and big data related to traffic is available, and efficient road network operation plans based on this have various effects, such as reducing travel time and waste of fuel. In order to facilitate traffic, a one-way road system can be introduced, which can be mainly used in a grid type road network.

In one-way traffic, it is possible to set the direction of travel alternately for each horizontal or vertical road in order for users to easily find the way, but considering the situation in which most drivers are familiar with the use of navigation and road structure, traffic flows smoothly. You can also set the direction of progress for the purpose of Moreover, since there are flows that occupy a large part of the traffic flow in the road network, it is desirable to allow them to easily move through a one-way traffic network.

For example, if there is a traffic flow from a point (1, white) to a point (1, black) in Fig. 1 and a traffic flow from the point (2, white) to the point (2, black), Each traffic flow can reach its destination in one turn (left or right turn) if the direction of one-way traffic is determined as shown by the thick arrow. Accordingly, an efficient road direction suitable for traffic flow can be given. In this case, a direction of an arbitrary direction may be given to roads whose direction is not determined, or a direction may be given alternately. Alternatively, these roads may be set as two-way traffic.

In FIG. 1, two traffic flows have been considered as examples, but when there are many flows to be considered preferentially, determining the direction of each road can be a very complicated problem. Furthermore, judging whether there is a one-way plan that facilitates these traffic flows can be a complex problem.

The road network planning apparatus 100 may receive information on a target road network and generate a road network plan for the target road network. The target road network refers to a road network that is a target of road network planning among a number of road networks. The information on the target road network may include road information (eg, a layout of a road) about roads included in the target road network, and driving route information about the driving paths of vehicles traveling on the target road network. Here, the driving route information may indicate at least one major traffic flow of the target road network.

The road network planning apparatus 100 allocates an identifier based on a boolean variable that distinguishes the forward direction and the opposite direction to each of the roads of the target road network, and assigns the driving routes included in the driving route information to the CNF (Conjunctive) of 2-SAT (satisfiability). Normal Form) and using Strongly Connected Component (SCC) to obtain a CNF solution, it is possible to determine the direction for one-way traffic on at least some of the roads.

2 is a diagram illustrating a target road network defined according to an embodiment. The road network planning apparatus may determine the directions of roads related to the corresponding flows when flows to be considered first in the target road network as shown in FIG. 2 are given. Although a grid type road network is shown in FIG. 2, embodiments are not necessarily limited to the grid type road network. In addition, the target road network of FIG. 2 is not a perfect grid, and some blocks are blocked by buildings, so that a detour is required.

Each intersection of roads can be identified by coordinates of (r- _x , c _y ), and each major traffic flow can be given as a starting point (r _x1 , c _y1 ) and an end point (r _x2 , c _y2 ). In determining the direction of the road, the main traffic flow is defined as having one or less turns (left or right turn) from the start point to the destination point. In relation to each road segment, the identifier of H _i or V _j is displayed, and different identifiers are assigned to segments that are not consecutive even in the same row or column. A road segment may simply be referred to as a road. In the case of H ₃₁ in Fig. 2, the identifier of H ₄₁ may be assigned. H ₃₁ and H ₃₂ belong to the same line but have different identifiers.

The road network planning apparatus may determine the direction of each road segment based on the information of the target road network. As described above, the road segment to which directionality is given may be at least a part of the entire road segment of the target road network. The identifier of each road segment may correspond to a Boolean variable, and the direction of each road segment may be expressed as a value of a Boolean variable (true/false, +/-). In this case, the directionality of each road segment can be modeled as 2-SAT.

For example, if the target road network is a grid-type road network including horizontal roads and vertical roads, in the case of horizontal roads, the right direction is viewed as the forward direction (and vice versa), the right direction is true (+), and the left direction is It can be expressed as false (-). In the case of a vertical road, the downward direction can be viewed as a forward direction (and vice versa), the downward direction as true (+), and the upward direction as false (-). Accordingly, the road network planning apparatus is a first boolean variable having a true value for a first horizontal direction among horizontal roads and a false value for a second horizontal direction opposite to the first horizontal direction. A first identifier corresponding to is allocated, and a first vertical road among vertical roads has a true value for a first vertical direction and a false value for a second vertical direction opposite to the first vertical direction. 2 A second identifier corresponding to a boolean variable can be assigned.

3 to 6 are diagrams illustrating path types according to an embodiment. As shown in FIGS. 3 to 6, the required direction of each road varies depending on the location of the starting point and the arrival point, and the path type of the driving route may be determined according to the pattern of the starting point and the arrival point. 3 to 6 correspond to different path types, respectively.

The direction of a predetermined pattern can be given for each path type. In the case of FIG. 3, the direction of a(+), d(+) or b(+), c(+) is required. In the case of FIG. 4, the direction of a(+), d(-) or b(-), c(+) is required, and in the case of FIG. 5, a(-), d(+) or b(+), c( The direction of -) is required, and in the case of FIG. 6, the direction of a(-), d(-) or b(-), c(-) is required. According to this direction, a logical expression having a predefined format for each path type may be matched. For example, a logical expression of ad+bc is matched with the path type of FIG. 3, the logical expression of ad'+b'c is matched with the path type of FIG. 4, and a'd+bc' is matched with the path type of FIG. The logical expression may be matched, and the logical expression a'd'+b'c' may be matched to the path type of FIG. 6.

If the direction of the road is expressed as xy+uv, etc. in a logical expression by a called variable, it is equivalent to (x+u)(x+v)(y+u)(y+v) according to the Boolean algebra. Accordingly, when there are multiple flows, the road direction requirement can be expressed as a continuous logical product, and each clause in DNF (Disjunctive Normal Form) can be expressed as a logical sum of up to two logical variables. . This can result in a 2-SAT problem, and a solution can be found by converting to a Strongly Connected Component (SCC). SCC can be based on the Kosraju algorithm.

According to an embodiment, the road network planning apparatus uses a plurality of logical expressions each having a predefined format for various route types, and clauses standardized in advance corresponding to the plurality of logical expressions. Can be expressed as CNF of 2-SAT. For example, the road network planning apparatus determines the route type of the first driving route among the driving routes of the driving route information, and corresponds to the route type of the first driving route among a plurality of logical expressions having a predefined format. Select a logical expression of the format, select a first clause corresponding to the logical expression of the first type from among the pre-normalized clauses corresponding to each logical expression, and the above in the first clause At least part of the CNF may be expressed by substituting the first identifier of the first driving route.

7 is a diagram illustrating a process of obtaining a CNF solution using SCC according to an embodiment. The SAT determines whether there is a set of values for each logical variable that makes a given expression true, which is the first recognized NP problem. In the case of a 2-SAT problem, the answer can be obtained in polynomial time. In the logical sum (x+y), if x is false, y must be true, and if y is false, x must be true. Can be used.

이후 Kosaraju 알고리즘으로 SCC를 구할 수 있다. 만약 논리 변수 x_i와 ~x_i가 같은 그룹에 속한다면 답이 없는 것이고, x_i에서 ~x_j까지 경로만 있으면 x_i는 거짓이다. 반대로, ~x_i에서 x_j로의 경로가 있으면 x는 참이다. 경로가 존재하지 않는다면, Don`t care 항이 된다.As shown in Fig. 7, a node of true and false is created for all logical variables (x1 to x4), respectively, and links of ~x _i →x _j and ~x _j →x _i are made for the (x _i +x _j ) term. Connect.

After that, the SCC can be obtained using the Kosaraju algorithm. If the logical variables x _i and ~x _i belong to the same group, there is no answer, and if there is only a path from x _i to ~x _j , x _i is false. Conversely, if there is a path from ~x _i to x _j , then x is true. If the path does not exist, it becomes a Don`t care term.

In this way, in order to solve the one-way traffic problem in the road network with 2-SAT, each logical variable must be defined and the DNF composed of the logical variables must be defined. Here, in each logical sum term, the number of logical variables must be 2 or less. As shown in FIG. 2, each road segment may be defined as one logical variable. A boolean variable can be defined so that any one direction is selected as the forward direction and is true in the forward direction and false in the opposite direction. For example, in the case of a horizontal road, the right direction may be true, and in the case of a vertical road, the downward direction may be true.

The indexes of the identifiers of the segments of each road may be sequentially assigned in a certain direction, and as shown in FIG. 2, indexes may be assigned to increase from left to right and from top to bottom (V ₁ to V ₃ and H ₁ to H ₇ ). . In addition, the intersection of each road is defined as (r _x , c _y ), and the mutual positional relationship between the two intersections can be grasped by comparing the size of the index. Each coordinate has the index of the vertical or horizontal segment to which it belongs. For example, the horizontal segment of (a, b) is expressed as A, and the vertical segment is expressed as B.

If A==C or B==D for each traffic flow (a, b) → (c, d), this means that a straight path from the start point to the destination point is formed without rotation. In (a, b) → (a, d), if b <d, it goes to the right from row H to which a belongs. In this case, since H must be true, the logical expression becomes a. This can be expressed as (A+0)=(A+xx')=(a+x)(a+x'). Here, x is an arbitrary logical variable. If b>d, it can be expressed as (A'+x)(A'+x') in the same principle. If it belongs to the same column, that is, if b==d, it can be expressed as DNF in the same way.

For each traffic flow (a, b)→(c, d), if a!=c and b!=d, links to a→c, b→d exist, the positions of a and c, b and d Depending on, it is possible to generate a logical expression as shown in FIGS. 3 to 6. On the other hand, if the link of a→c does not exist, that is, the road in row a is disconnected (e.g., the path corresponding to (r ₃ , c ₁ ) → (r ₅ , c ₃ ) in FIG. 2), (r ₃ , c ₁ )→(r ₃ , c ₃ )→(r ₅ , c ₃ ) or (r ₃ , c ₁ )→(r ₅ , c ₁ )→(r ₅ , c ₃ ).

If (r ₃ , c ₁ ) and (r ₃ , c ₃ ) are not connected, the first case cannot exist, so the second method is (r ₃ , c ₁ )→(r ₅ , c ₁ )→(r _{Only 5} , c ₃ ) can be considered. If the second route is also disconnected, there is no one-way plan that arrives with less than one turn for this traffic flow. If there is an unbroken path only for either the first path or the second path, the logical expression will have the same form as AD, which is AD=AD+xx'=(A+x)(A+x')(D+ It can be expressed in the form of x)(D+x').

Therefore, 1) if it can be reached without rotation (a type that runs straight in the horizontal direction and a type that runs straight in a vertical direction), 2) horizontal → vertical (a type that travels by rotating in a vertical direction after driving in the horizontal direction), vertical → In the case that it is possible to reach the two routes horizontally (the type of driving in the vertical direction and then rotating in the horizontal direction), 3) All cases, including the case where only one of the above two routes can be reached due to a broken road, can be expressed in DNF. In addition, even in a complex road network as shown in FIG. 2, when major flows are given, a one-way plan can be efficiently established.

8 is a flow chart showing a road network planning method according to an embodiment. Referring to FIG. 8, in step 810, the road network planning apparatus receives road information and driving route information about a target road network. The road information may include a layout of roads included in the target road network, and the driving route information may include at least one major traffic flow of the target road network. In step 820, the road network planning apparatus allocates an identifier based on a boolean variable to roads of the target road network. Therefore, the forward direction and the opposite direction can be distinguished through the identifier.

In step 830, the road network planning apparatus may express the driving paths of the target road network as CNF of 2-SAT. The driving paths may be expressed as a continuous logical product of clauses of the 2-SAT expressed as a logical sum of two logical variables (boolean variables) as shown in FIG. 7. In step 840, the road network planning apparatus may obtain a CNF solution using the SCC. In step 850, the road network planning apparatus may determine a direction for one-way traffic with respect to at least some of the roads based on the solution of the CNF. The CNF solution can include the values (true/false) of each logical variable, and each direction can be determined accordingly.

9 is a block diagram showing an apparatus for planning a road network according to an embodiment. Referring to FIG. 9, the road network planning apparatus 900 includes a processor 910 and a memory 920. The memory 920 is connected to the processor 910 and may store instructions executable by the processor 910, data to be calculated by the processor 910, or data processed by the processor 910. Memory 920 includes non-transitory computer-readable media, such as high-speed random access memory and/or non-volatile computer-readable storage media (e.g., one or more disk storage devices, flash memory devices, or other non-volatile solid state memory devices). Can include.

The processor 910 may execute instructions for executing one or more operations described with reference to FIGS. 1 to 8. For example, the processor 910 receives road information about roads included in the target road network, and driving route information about the driving paths of vehicles traveling on the target road network, and a boolean variable that distinguishes the forward direction and the opposite direction. The base identifier is assigned to each of the roads, and the driving paths included in the driving path information are expressed in a 2-SAT (satisfiability) CNF (Conjunctive Normal Form) using a boolean variable, and a Strongly Connected Component (SCC) is used. Thus, the CNF solution may be obtained, and, based on the obtained CNF solution, the direction for one-way traffic may be determined for at least some of the roads.

The apparatus described above may be implemented as a hardware component, a software component, and/or a combination of a hardware component and a software component. For example, the devices and components described in the embodiments are, for example, a processor, a controller, an Arithmetic Logic Unit (ALU), a digital signal processor, a microcomputer, a Field Programmable Gate Array (FPGA). , PLU (Programmable Logic Unit), a microprocessor, or any other device capable of executing and responding to instructions, it may be implemented using one or more general purpose computers or special purpose computers. The processing device may execute an operating system (OS) and one or more software applications executed on the operating system. In addition, the processing device may access, store, manipulate, process, and generate data in response to the execution of software. For the convenience of understanding, although it is sometimes described that one processing device is used, one of ordinary skill in the art, the processing device is a plurality of processing elements and/or a plurality of types of processing elements. It can be seen that it may include. For example, the processing device may include a plurality of processors or one processor and one controller. In addition, other processing configurations are possible, such as a parallel processor.

The software may include a computer program, code, instructions, or a combination of one or more of these, configuring the processing unit to behave as desired or processed independently or collectively. You can command the device. Software and/or data may be interpreted by a processing device or to provide instructions or data to a processing device, of any type of machine, component, physical device, virtual equipment, computer storage medium or device. , Or may be permanently or temporarily embodyed in a transmitted signal wave. The software may be distributed over networked computer systems and stored or executed in a distributed manner. Software and data may be stored on one or more computer-readable recording media.

The method according to the embodiment may be implemented in the form of program instructions that can be executed through various computer means and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like alone or in combination. The program instructions recorded on the medium may be specially designed and configured for the embodiment, or may be known and usable to those skilled in computer software. Examples of computer-readable recording media include magnetic media such as hard disks, floppy disks, and magnetic tapes, optical media such as CD-ROMs and DVDs, and magnetic media such as floptical disks. -A hardware device specially configured to store and execute program instructions such as magneto-optical media, and ROM, RAM, flash memory, and the like. Examples of the program instructions include not only machine language codes such as those produced by a compiler, but also high-level language codes that can be executed by a computer using an interpreter or the like. The hardware device described above may be configured to operate as one or more software modules to perform the operation of the embodiment, and vice versa.

As described above, although the embodiments have been described by the limited embodiments and drawings, various modifications and variations are possible from the above description by those of ordinary skill in the art. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved.

Therefore, other implementations, other embodiments, and claims and equivalents fall within the scope of the claims to be described later.

Claims (8)

In the operation method of the road network planning device,
Receiving road information on roads included in a target road network and driving route information on a driving route of vehicles traveling on the target road network;
Allocating to each of the roads an identifier based on a boolean variable that distinguishes a forward direction and an opposite direction;
Expressing the driving paths included in the driving path information in a Conjunctive Normal Form (CNF) of 2-SAT (satisfiability) by using the Boolean variable;
Obtaining a solution of the CNF using a Strongly Connected Component (SCC); And
Based on the obtained solution of the CNF, determining a direction for one-way traffic with respect to at least some of the roads
Including,
The step of expressing the driving routes in the CNF
Determining a path type of a first driving path among the driving paths;
Selecting a first type of logical expression corresponding to the route type of the first driving route from among a plurality of logical expressions each having a predefined format for various route types;
Selecting a first clause corresponding to the logical expression of the first type from among clauses pre-normalized corresponding to the plurality of logical expressions; And
Substituting the first identifier of the first driving route in the first section to represent at least a part of the CNF
Containing, operating method. The method of claim 1,
The target road network is a grid-type road network including horizontal roads and vertical roads,
Allocating the identifier
A first boolean variable corresponding to a first horizontal road among the horizontal roads, which has a true value with respect to a first horizontal direction and a false value with respect to a second horizontal direction opposite to the first horizontal direction Assigning an identifier; And
A second boolean variable corresponding to a first vertical road among the vertical roads, having a true value with respect to a first vertical direction and a false value with respect to a second vertical direction opposite to the first vertical direction Steps to assign an identifier
Containing, operating method. delete The method of claim 1,
The various route types are
The first type running straight in the horizontal direction, the second type running straight in the vertical direction, the third type running in the horizontal direction and then rotating in the vertical direction, and the third type running in the vertical direction and then rotating in the horizontal direction. Containing 4 types,
How it works. A computer-readable storage medium storing one or more programs including instructions for performing the method of any one of claims 1, 2 and 4. Processor; And
A memory containing instructions executable in the processor
Including,
When the instructions are executed in the processor, the processor
Receiving road information on roads included in the target road network and driving route information on driving routes of vehicles traveling on the target road network,
Allocating an identifier based on a boolean variable that distinguishes the forward direction and the opposite direction to each of the roads,
Expressing the driving paths included in the driving path information in 2-SAT (satisfiability) CNF (Conjunctive Normal Form) using the Boolean variable,
Acquire the solution of the CNF using Strongly Connected Component (SCC),
Based on the solution of the obtained CNF, determine a direction for one-way traffic with respect to at least some of the roads,
In expressing the travel paths in the CNF,
The processor is
Determining a path type of a first driving path among the driving paths,
Selecting a first type of logical expression corresponding to the route type of the first driving route from among a plurality of logical expressions each having a predefined format for various route types,
Selecting a first clause corresponding to the logical expression of the first type from among clauses standardized in advance corresponding to the plurality of logical expressions,
Substituting the first identifier of the first travel route in the first section to represent at least a portion of the CNF,
Road network planning device. The method of claim 6,
The target road network is a grid-type road network including horizontal roads and vertical roads,
The processor is
A first boolean variable corresponding to a first horizontal road among the horizontal roads, which has a true value with respect to a first horizontal direction and a false value with respect to a second horizontal direction opposite to the first horizontal direction Assign an identifier,
A second boolean variable corresponding to a first vertical road among the vertical roads, having a true value with respect to a first vertical direction and a false value with respect to a second vertical direction opposite to the first vertical direction Assigning an identifier,
Road network planning device. delete

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