WO2014003321A1

WO2014003321A1 - Start point-based traffic allocation method using shortest path

Info

Publication number: WO2014003321A1
Application number: PCT/KR2013/004640
Authority: WO
Inventors: 조중래
Original assignee: 명지대학교 산학협력단
Priority date: 2012-06-27
Filing date: 2013-05-28
Publication date: 2014-01-03
Also published as: KR101347603B1

Abstract

The present invention relates to a starting point-based traffic allocation method using the shortest path which predicts how many cars actually pass over a road and which is then used in the field of road planning in order to analyze the traffic conditions of a corresponding road and nearby roads when the road is newly constructed or extended. The method has the effect of greatly reducing the time taken for a search and of increasing work efficiency by shortening the considerable time expended for doing related work in the field of traffic planning.

Description

Starting point-based traffic assignment method using the shortest path

The present invention relates to a starting point-based traffic assignment method using the shortest route. More particularly, the present invention relates to a road and surrounding road as a new road is newly expanded or expanded by using a road planning field to predict how the vehicle will pass on the actual road. The present invention relates to a method of assigning traffic for the starting point period using the shortest path for analyzing traffic conditions.

Among the traffic allocation techniques, there are three types of conventionally developed techniques for searching for balanced traffic. First is the Frank-Wolf algorithm, which is the most commonly used algorithm from the past to the present, and the second is a path-based algorithm that is not practical. Third is the Origin-based algorithm.

However, the Frank-wolf algorithm is a technique introduced in the 1960s and is used in most traffic S / Ws to find the optimal solution in nonlinear programming. However, the accuracy is inferior, and the path-based algorithm is the current level of computer memory. Considering this, there is a problem that it is impossible to apply to a network, and the Origin-Based algorithm has 2-3 times more precision than the Frank-Wolf, and it is installed in the recent traffic S / W but traffic demand increases. As a result, the execution time increases rapidly.

The present invention was created to solve the above-mentioned problems, the starting point-based traffic assignment method using the shortest path to significantly improve the accuracy of the analysis results to ensure the reliability of analysis results and to shorten the analysis time to increase the efficiency of transportation work The purpose is to provide.

In order to achieve the above object, a starting point-based traffic assignment method using the shortest path according to the present invention includes (a) a control point of the starting point-based traffic assignment server using the shortest path for all paths stored in the basic network DB of the database unit. Reading a model point connecting a starting point and an arrival point from a basic network; (b) generating a bush network by extracting only a route from the basic network to an arrival point where traffic demand exists based on a starting point in the basic network; (c) transitioning from a Bush network composed of a link list to a branch network composed of only nodes that are classified and joined in the Bush network; (d) a maximum and minimum path searching unit searching for a short path (min-path) and a long path length (max-path) in the branch network; (e) assigning the traffic volume so that the traffic transition unit has the same travel time on the minimum path and the maximum path; (f) determining whether the control unit 120 reaches a balance point at which the minimum and maximum path travel times are the same as the traffic volume transition in step (e); And (g) in step (f) above, when the minimum and maximum path travel times reach the same balance point, the control unit searches for (d) step and traffic volume to search for the minimum and maximum path to maintain the balance point. And repeatedly performing the step of transferring (e).

The starting point-based traffic assignment method using the shortest route according to the present invention has the effect of significantly reducing the time required for searching, compared to the prior art, and thus, a considerable time in carrying out related tasks in the field of traffic planning. It has the effect of increasing work efficiency by shortening the time.

1 is a block diagram of a server for providing a starting point-based traffic assignment method using the shortest path according to the present invention;

Figure 2 is a term explanatory diagram for explaining the assignment method based on the starting point using the shortest path according to the present invention,

3 is an algorithm of a starting point-based traffic assignment method using the shortest path according to the present invention;

4 is a sub-algorithm of the starting point-based traffic assignment method using the shortest path according to the present invention, and

5 is another sub-algorithm of the starting point-based traffic assignment method using the shortest path according to the present invention.

Hereinafter, with reference to the accompanying drawings will be described in detail an embodiment of the present invention. Prior to this, terms or words used in the present specification and claims should not be construed as being limited to the ordinary or dictionary meanings, and the inventors should properly explain the concept of terms in order to best explain their own inventions. Based on the principle that it can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a server block for providing a starting point-based traffic assignment method using the shortest path according to the present invention.

As shown in FIG. 1, a traffic assignment server based on a starting point using the shortest path according to the present invention includes a bush network generation unit 110, a control unit 120, a bush update unit 130, and a bush-branch transition unit 140. And a maximum and minimum route search unit 150, a traffic transition unit 160, and a database unit 170.

Prior to the description of the above configuration, with reference to FIG. 2 for terms frequently used in the present specification, the basic network is a term generally representing a road network, as shown in FIG. The bush network is a sub network of a path that can reach a plurality of destinations based on one starting point as shown in (b) of FIG. 2, and the branch network is a single network as shown in (c) of FIG. 2. It is a Sketch network made up of only nodes that are classified and joined in Bush.

In addition to the bush described above, it means a sub network that does not have a cycle (cycle) connecting all the arrival points around one starting point, where the cycle up is a specific position on the path connecting the terminal point Means a network with no repeated paths.

Meanwhile, the bush network generation unit 110 searches for the shortest path between the terminal points in demand, and adds the bush network to the bush by adding a link on the path connecting all the terminal points with traffic demands from one starting point. Create

The bush update unit 130 first removes the link in the bush without traffic and then searches for the shortest path between new model points and updates by adding a link on the path to the bush when a new path exists.

The bush generated by the bush network generation unit 110 increases the size of the network as it stores all the links on the path, and accordingly increases the search time of the maximum and minimum paths in the memory and the bush.

Accordingly, the Bush-Branch transition unit 140 transfers to the branch network of the tree reconstructed by only the points that are sorted or joined in the tree structure Bush to prevent the increase in the specific gravity of the memory and shorten the search time.

For reference, although the Bush-Branch transition unit 140 is described as transferring the Bush to the branch, the branch may be transferred back to the Bush.

The maximum and minimum path search unit 150 searches for a minimum path (min-path) having a short passage time and a maximum path (max-path) having a long passage time in the branch generated by the branch transition unit 140.

On the other hand, the traffic volume transfer unit 160 moves the traffic volume so that the travel time on the two paths are the same, more specifically, the travel time on the path is an increase function for the traffic volume, and passes the traffic volume of the maximum path with a long path travel time. By moving to the shortest time path, the minimum and maximum paths are equal.

That is, the traffic transition unit 160 transfers the traffic volume in two or more paths on the Bush network as described above so that the vehicle moving in each path may take the same travel time.

At this time, the control unit 120 is moved by the traffic volume transfer unit 160, the traffic volume of the maximum path with a long path passage time is moved to the minimum path with a short passage time, the passage time of the minimum path and the maximum path is equal to the balance point. Determine if you have reached it.

As mentioned above, the database unit 170 is a basic network DB 171 in which information on a road network basic network is generally stored, as shown in FIG. As shown in FIG. 2C, the Bush network DB 172 storing the Bush network, which is a sub network of a path that can reach a plurality of destinations based on one starting point, is classified in one Bush, It includes Branch Network DB 173, which is a sketch network made up of only joining nodes.

The allocation method based on the starting point using the shortest path by the server having the above-described configuration will be described in detail with reference to FIG. 3.

3 is an algorithm of a starting point-based traffic assignment method using the shortest path according to the present invention.

First, the term node used in an embodiment of the present invention means an intersection, a road confluence point, an intersection point of an intersection and a road, and the term link used in an embodiment of the present invention connects a node and a node. Road, that is, a road between an intersection and an intersection, a road between a road junction and a road junction, and a road between an intersection and a road junction.

First, the control unit 120 performs a step of reading the model point from the basic network DB 161 in which all the path networks of the specific region including the node and the link are stored (S10).

That is, in step (S10), the control unit 120 reads all paths connecting the starting point (O: Origin), which is a starting point, and the ending point (D: Destination), which is a starting point, for the passenger to perform his or her activities.

Subsequently, the Bush network generator 110 extracts only a route from the basic network to an arrival point where traffic demand exists based on the starting point, and configures a bush network as shown in Table 1 below. When a new path according to the change exists, adding the path to create a bush network (S20).

Table 1

Step 0: Search Minpath-Search for the best path for a single starting point. Step 1: Add to Initial Bush-Extract the route to all destinations and add the link on the route to the Bush list-Add traffic demand between one model point to the link traffic on the route Step 2: Ordering-Bush only link list Have. The process of assigning network concepts such as connectivity between each link is an ordering process.-Step 2-0: Initialize Indegree, Outdegree, Order = 0, List (1) = Starting Point nList = 1, next = 0-Step 2-1 : Count inbound / outbound Link-Step 2-2: Operation List id = List (nL) List (nL) = 0 nL = nL-1-Step 2-3: Ordering next = next + 1 Order (next) = id- Step 2-4: Update Indegree for i = 1, outdegree (id) Indegree (i) = indegree (i)-1 if (indegree (i) = 0) then nL = nL + 1; List (nL) = I-Step 2-5: check List if List (1) = 0 then stop, else goto Step 2-2;

Referring to Table 1 above, the Bush network generation step will be described with reference to FIG. 4. The maximum and minimum path searching unit 140 searches for an optimal path for each starting point. Performing a step (S21), and the bush network generating unit 110 extracts a path from the starting point to all the arrival points and adds a link on the path to the bush list (S22), and one model point (S23) adding the traffic demand between the departure point and the arrival point to the link traffic on the route, and ordering to create a bush network by giving a network concept through the link between the link lists added to the bush list. Step S24 is performed.

For reference, FIG. 4 is a sub-algorithm of a starting point based traffic assignment method using the shortest path according to the present invention.

The Bush-Branch transition unit 140 performs a step of transitioning to a branch network made up of only nodes that are classified and joined in a Bush network composed of only a link list as shown in Table 2 below (S30).

TABLE 2

Step 1: Check the number of outbound if Outbound> 1) then next step; Step 2: count branch (k) k = k + 1-Step 3: count sub link in branch t = t + 1-Step 4: Save Infomation BranchVolume (t) = BushVolume (k, t) n = n + 1 BranchLink (t, n) = Bush (k, t) if outbound of bush (k, t)> 1 then goto step 3

Transitioning to the branch network is that the size of the network increases as the bush network generated by the bush network generation unit 110 stores all the links on the path, and accordingly, searching for the minimum path and the maximum path in the memory and bush. This is to reduce the memory capacity and shorten the search time because the time increases.

The maximum and minimum path search unit 150 has a short path time and a long travel time in the branch network transitioned from the Bush network by the branch transition unit 140 as shown in [Table 3]. The search for the maximum path (max-path) is performed (S40).

TABLE 3

Step 0: Initialize minBackID, maxBackID, minTime, maxTime, SplitParent, SplitEndLink = 0-for from branch i-Step 1: Branch Travel Time (time) for to branch j Aggregate-Step 2: Check minpath for to branch j if minTime (from) + time <minTime (to) then minTime (to) = minTime (from) + time minBackID (to) = j minlable (lto) = I-Step 3 : Check maxpath for to branch j if maxTime (from) + time> maxTime (to) then maxTime (to) = maxTime (from) + time maxBackID (to) = j maxlable (lto) = I-Step 4: check split if minBackID (i) / = maxBackID (j) and minlabel (i) = maxlabel (i) then nS = nS + 1 SplitParent (nS) = Order (minlabel (i)) SplitEndLink (nS) = i

When the search for the minimum path and the maximum path is made, the traffic transition unit 160 performs a step of moving the traffic volume so that the travel time on the two paths (the minimum path and the maximum path) is the same. [Table 4] In more detail with reference to, the passage time on the route is an increase function for the traffic volume, and the minimum route and the maximum route are the same by moving the traffic volume of the maximum route with a long route passage time to the minimum route with a short passage time. A traffic transition step is performed (S50).

That is, in step 'S50', the traffic transition unit 160 is divided into a minimum path and a maximum path in the Bush network. Use the derivative value.

Table 4

-for all Split-Step 0: Initialize minTime, minDiffTime, maxTime, maxDiffTime-Step 1: min path section minTime = minTime + linktime minDiffTime = minDiffTime + difflinktime-Step 2: max path section minTime = minTime + linktime minDiffTime = minDiffTime + difflinktime -Step 3: calculate shift volume shift volume = maxTime minTime / (minDiffTime + maxDiffTime)-Step 4: Correction of the amount of transition-This is a unique part of this technology, and virtually substitutes the amount of transition calculated in Step 3 to minsection and maxsection It is a technique to reduce the travel time difference between minsection and maxsection by predicting the changing travel time-shift volume = maxTime minTime / (minTime2-maxTime2 + maxTime minTime)-Step 5: update volume and time-the final calculated in Step 4 Shift volume is added to links and branches in minsection and subtracted to links and branches in maxsection. -Recalculate link travel time according to changed traffic volume

On the other hand, the control unit 120 performs a step of determining whether a balance point at which the passage time of the minimum route and the maximum route reaches the same as the traffic volume transition (S60).

In the step S60, when the minimum and maximum path travel times reach the same balance point, the control unit 120 has a minimum path (min-path) with a short travel time by the maximum and minimum path search unit 150. Searching for the maximum path (max-path) having a long travel time (S40) and repeatedly performing the traffic transition step (S50) such that the minimum path and the maximum path by the traffic transition unit 160 are the same. Ensure that the current equilibrium point is maintained between the minimum and maximum travel times.

If the balance point is not reached at step S60, the bush update unit 130 deletes the element that prevents the balance point from being reached and updates the bush network at step S70.

Subsequently, the controller 120 determines whether the network has reached the balance point (S80), and when the balance point is reached, re-performs the step S40 after searching for the minimum path and the maximum path, and does not achieve the network balance point. If not, the allocation method algorithm ends.

In more detail, step S70 of deleting an element that prevents reaching the balance point and updating the bush network will be described in detail with reference to FIG. 5.

For reference, FIG. 5 is another sub-algorithm of the starting point-based traffic assignment method using the shortest path according to the present invention.

When the traffic transition step (S50) is completed, as shown in [Table 5], the control unit 120 there is a case where the traffic amount is close to zero in a particular branch, in this case the maximum and minimum Since it affects the path search, the step of deleting the zero branch is performed (S71).

Table 5

-Step 1: calculate inbound volume-Step 2: check zero branch-Whether the inbound volume is below a certain value (1.0 * 10-15) close to 0-Step 3: delete branch-Delete branch information and branch volume information

In the step S71, the branch network from which the zero branch is deleted is reversed from the step S30, and the branch network including nodes in which the Bush-Branch transition unit 140 is classified and joined as shown in [Table 6] is linked. Transition to the bush network consisting of (S72).

Table 6

-for all branch point-Step 1: count outbound j = j + 1-Step 2: check branch volume if branch volume> 0 then BushList = BranchLink BushVolume = BranchVolume

The control unit 120 checks whether a link on the new route exists in the Bush network, and if the link is not included in the Bush network, the traffic volume is transferred to the Bush network transitioned in step S72 in step S50. In step S73, a new optimal path in the changed traffic situation is added to the bush list and updated.

Subsequently, the Bush network generation unit 110 assigns a network concept to a Bush list in which a cycle exists as shown in [Table 7] through a link between link lists added to the Bush list to establish a Bush network. After generating the ordering (Ordering) step and searching for and removing a path that repeats a specific location on the path that causes the cycle, that is, the path connecting the terminal point, and performs the step of generating a bush network (S74).

TABLE 7

Step 0: Search Minpath Step 1: Add to Bush Step 1-1: Check if a link on the new path exists in Bush Step 1-2: Add to Bush list if it is not included in Bush Step 2: OrderingWithCycle-cycle This technique is to complete the cycle after performing ordering on the existing bush, searching for and removing the link that causes the cycle. Step 2-0: Initialize-Step 2-1: Count inbound / outbound Link-Step 2-2: Operation List-Step 2-3: Ordering-Step 2-4: Update Indegree-Step 2-5: check List if List (1) = 0 and all Indegree = 0 then stop else for new bush k if indegree (k) = 1 and orgIndegree (k) / = indegree (k) then Indegree (k) = 0 Outdegree (k) = Outdegree ( k)-1 List (nL) = 0 goto Step 2-2

The Bush-Branch transition unit 140 performs a step of transitioning to a branch network which is generated only in a node network which is generated in step S74 and classified and joined in a bush network composed only of a link list (S75).

The bush update unit 130 deletes the variable that prevents the bush network from reaching the balance point, and when the bush network is updated, the minimum path and the maximum path are searched by the maximum and minimum path search unit 150. The 'S40' step is performed again.

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

Claims

(a) A model in which the control unit 120 of the starting point-based traffic assignment server 100 using the shortest path connects the starting point and the arrival point from the basic network for all the paths stored in the basic network DB 161 of the database unit 160. Reading a point;

(b) the bush network generating unit 110 of the server 100 generating a bush network by extracting only a route from the basic network to an arrival point where traffic demand exists based on the starting point;

(c) the Bush-Branch transition unit 140 of the server 100 transitioning to a branch network consisting of only nodes that are classified and joined in the Bush network composed of a link list;

(d) a step of searching the maximum and minimum path search unit 150 of the server 100 by searching for the minimum path (min-path) with a short passage time and the maximum path (max-path) with a long lifetime in the branch network. ;

(e) the traffic transfer unit 160 of the server 100 allocating the traffic volume so that the travel time on the minimum path and the maximum path is the same;

(f) determining whether the control unit 120 of the server 100 reaches a balance point at which the minimum path and the maximum path travel time are the same as the traffic volume transition in the step (e); And

(g) when the passage time of the minimum path and the maximum path reaches the same balance point in step (f), the control unit 120 searches for the minimum path and the maximum path to maintain the balance point. (d) repeating the `(e)` step of transferring the step and traffic volume; and a starting point-based traffic assignment method using the shortest path.
The method of claim 1,

Step (b) is

(b-1) searching for the optimal path with respect to the starting point by the maximum and minimum path searching unit 140;

(b-2) the bush network generating unit 110 extracting a path from the starting point to all the arrival points and adding a link on the path to the bush list;

(b-3) adding, by the Bush network generating unit 110, the traffic demand between one model point (starting point and arrival point) to the link traffic on the corresponding route; And

(b-4) an ordering step of generating the Bush network by giving the network concept through the connection between the link list added to the Bush list by the Bush network generating unit 110; Starting point-based traffic assignment using the shortest path.
The method of claim 1,

(h) In step (f), when the passage time of the minimum path and the maximum path does not reach the same balance point, the bush update unit 130 of the server 100 may set a variable that prevents reaching the balance point. Removing and updating the Bush network; Starting point-based traffic assignment method using the shortest path, characterized in that it further comprises.
The method of claim 3, wherein

The `(h)` step

(h-1) Upon completion of the step (e) of allocating traffic volume, the zero branch of which the traffic amount is close to zero affects the maximum and minimum path search, and the controller 120 controls the zero branch. Deleting;

(h-2) transitioning a branch network composed of nodes classified and joined by the Bush-Branch transition unit 140 to a Bush network composed of a link list;

(h-3) The controller 120 checks whether a link on a new path exists in the Bush network, and if the link is not included in the Bush network, the bush updater 130 determines the `(h-2). Updating and adding a new optimal route in the traffic situation changed through traffic volume transfer in the step (e) to the Bush network which has been transferred in step;

(h-4) ordering by reflecting the link list added to the Bush list by the Bush network generating unit 110, searching for and removing a repeated path, and regenerating the Bush network; And

(h-5) transitioning to the branch network so that the Bush-Branch transition unit 140 comprises only the nodes that classify and join the Bush network regenerated in step (h-4). Starting point-based traffic assignment method using the shortest path.
The method of claim 4, wherein

(i) When the bush network is updated by the bush updater 130, the controller 120 searches for the minimum path and the maximum path by the maximum and minimum path search units 150, and (d). The method according to claim 1, further comprising the step of reaching a balance point by controlling to perform the steps after step).