• Journal of Korean Society of Transportation
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• v.22 no.4 s.75
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• pp.85-96
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• 2004

Given a Path represented by a sequence of link numbers in a transportation network, the reasonable path is defined as a path that any link is appeared multiple times in it. Application of the link labelmethod(LLM) to the shortest path algorithms(SPA) enables to model the reasonable path choice behavior in urban networks. This study aims at expanding the LLM to a Kth shortest path algorithms(KPSA), which adopts the node label setting method. The small-scaled network test demonstrated that the proposed algorithm works correctly and the revised Sioux fall network test showed that the path choice behaviors are reasonably reflected. In the large-scaled network based on the South Korea peninsula, drivers' route diversion perceptions are included as cost terms in total cost. The algorithm may be applied as an alternative route information tools for the deployment of ATIS.

• Journal of Korean Society of Transportation
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• v.22 no.2 s.73
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• pp.131-143
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• 2004

Given a path represented by a sequence of link numbers in a graph, the vine is differentiated from the loop in a sense that any link number can be visited in the path no more than once, while more than once in the loop. The vine provides a proper idea on complicated travel patterns such as U-turn and P-turn witnessed near intersections in urban transportation networks. Application of the link label method(LLM) to the shortest Path algorithms(SPA) enables to take into account these vine travel features. This study aims at expanding the LLM to a K-th path search algorithm (KPSA), which adopts the node-based-label correcting method to find a group of K number of paths. The paths including the vine type of travels are conceptualized as drivers reasonable route choice behaviors(RRCB) based on non-repetition of the same link in the paths, and the link-label-based MPSA is proposed on the basis of the RRCB. The small-scaled network test shows that the algorithm sequence works correctly producing multiple paths satisfying the RRCB. The large-scaled network study detects the solution degeneration (SD) problem in case the number of paths (K) is not sufficient enough, and the (K-1) dimension algorithm is developed to prevent the SD from the 1st path of each link, so that it may be applied as reasonable alternative route information tool, an important requirement of which is if it can generate small number of distinct alternative paths.

• Journal of Korean Society of Transportation
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• v.22 no.6
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• pp.121-131
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• 2004

The K-shortest path algorithms are largely classified into two groups: oneis for finding loopless path (simple path), another loop paths. In terms of cimputational complexities, in general the loop-paths-finding ones are considered more efficient and easier to be handled than the loopless-paths-finding. The entire path deletion methods have been known as the best efficient algorithms among the proposed K-shortest path algorithms. These algorithms exploit the K-th network transformation to prevent the same path, which was already selected as the (K-1)th path, from being redetected. Nevertheless, these algorithms have a critical limitationto be applied in the practical traffic networks because the loops, in which the same modes and links can be unlimitedly repeated, are not preventable. This research develops a way to be able to selectively control loop-paths by applying link-label. This research takes an advantage of the link-based shortest path algorithms that since the algorithms can take care of two links simultaneouslyin the searching process, the generation of loops can be controlled in the concatenation process of the searched link and the preceded link. In concatenation of two links, since the precede link can be treated a sub-shortest to this link from the origination, whether both the node and the link of the searched link were already existed or not can be evaluated. Terefore, both the node-loopless path, in which the same node is not appeared, and the link-loopless, in which the same link is not appeared, can be separately controlled. Especially, the concept of the link-loopless path is expended to take into consideration reasonable route choice behaviors such as U-Turn, P-Turn, and Turn-Penalty, which are frequently witnessed in urban traffic network with intersections. The applicability of the proposed method is verified through case studies.