scholarly journals Algorithms for Finding Shortest Paths in Networks with Vertex Transfer Penalties

Algorithms ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 269 ◽  
Author(s):  
Rhyd Lewis

In this paper we review many of the well-known algorithms for solving the shortest path problem in edge-weighted graphs. We then focus on a variant of this problem in which additional penalties are incurred at the vertices. These penalties can be used to model things like waiting times at road junctions and delays due to transfers in public transport. The usual way of handling such penalties is through graph expansion. As an alternative, we propose two variants of Dijkstra’s algorithm that operate on the original, unexpanded graph. Analyses are then presented to gauge the relative advantages and disadvantages of these methods. Asymptotically, compared to using Dijkstra’s algorithm on expanded graphs, our first variant is faster for very sparse graphs but slower with dense graphs. In contrast, the second variant features identical worst-case run times.

2017 ◽  
Author(s):  
debby nurliza ulhaq ◽  
Budhy Soeksmantono ◽  
Ketut Wikantika

AbstrakMitigasi bencana merupakan salah satu hal penting yang harus dipertimbangkan terutama dalam konstruksi bangunan karena hal tersebut cukup rumit terlebih apabila dikaitkan dengan fakta tidak adanya informasi yang dapat digunakan untuk orang-orang menyelamatkan diri mereka sendiri. Maka dari itu, makalah ilmiah ini memperkenalkan mengenai network analysist untuk rute evakuasi darurat yang bertujuan untuk mencari rute terbaik menuju tempat aman seperti titik berkumpul tergantung pada situasi terkini. Pembuatan keputusan berdasarkan rute yang tepat akan dipilih berdasarkan kategori usia korban dan kondisi saat bencana terjadi, sehingga dapat mengurangi dampak buruk yang akan muncul. Algoritma Dijkstra menunjukan suatu algoritma perncarian rute terpendek antara gedung dan titik berkumpul dengan menghubungkan keduanya melalui data jalan. Model rute evakuasi ini dibentuk dengan menggunakan kombinasi antara model bangunan tiga dimensi yang dibangun dari data LiDAR, orthophoto, dan data lainnya yang berkaitan dengan pemodelan. Bangunan tiga dimensi dapat digunakan dalam manajemen bencana dan respon darurat karena dapat menyediakan informasi penting seperti lokasi bangunan. Evaluasi dari model yang diajukan meningkatkan kemampuan penyelamatan diri sendiri yang mengarah pada berkurangnya dampak buruk yang akan terjadi.Kata kunci: Evakuasi Darurat, Algoritma Dijkstra, LiDAR, pemodelan bangunan 3D AbstractMitigation is an important thing to be considered especially in building construction because it is quite complicated due to the fact that much of the information is unavailable for people to rescue themselves. Hence, this paper introduces about network analysis for evacuation emergency route which aims at finding the best route to the secured place such as the closest assembly point depends on the situation. Thus, decision making regarding the proper route to be chosen depends of the victim age category and current condition to minimize impact that can be generated. Dijkstra’s Algorithm is presented an algorithm for finding the shortest paths between building and assembly point by linking them through road data. This emergency evacuation route model is constructed by combining with three dimensional building model which constructed by using LiDAR data, orthophoto, and the other related data. Three dimensional geo data can be used in disaster management and emergency response because they may provide valuable information such as location of the building. The evaluation of the proposed model for a case study building improve self-sustaining which lead to chances of less adverse effects can appear.Keywords: Emergency Evacuation, Dijkstra’s Algorithm, LiDAR, 3D building model


2020 ◽  
Author(s):  
Teresa Rexin ◽  
Mason A. Porter

Traveling to different destinations is a big part of our lives. How do we know the best way to navigate from one place to another? Perhaps we could test all of the different ways of traveling between two places, but another method is using mathematics and computation to find a shortest path. We discuss how to find a shortest path and introduce Dijkstra’s algorithm to minimize the total cost of a path, where the cost may be the travel distance or travel time. We also discuss how shortest paths can be used in the real world to save time and increase traveling efficiency.


2019 ◽  
Vol 1 (2) ◽  
pp. 41-45
Author(s):  
Md. Almash Alam ◽  
Md. Omar Faruq

Roads play a Major role to the people live in various states, cities, town and villages, from each and every day they travel to work, to schools, to business meetings, and to transport their goods. Even in this modern era whole world used roads, remain one of the most useful mediums used most frequently for transportation and travel. The manipulation of shortest paths between various locations appears to be a major problem in the road networks. The large range of applications and product was introduced to solve or overcome the difficulties by developing different shortest path algorithms. Even now the problem still exists to find the shortest path for road networks. Shortest Path problems are inevitable in road network applications such as city emergency handling and drive guiding system. Basic concepts of network analysis in connection with traffic issues are explored. The traffic condition among a city changes from time to time and there are usually huge amounts of requests occur, it needs to find the solution quickly. The above problems can be rectified through shortest paths by using the Dijkstra’s Algorithm. The main objective is the low cost of the implementation. The shortest path problem is to find a path between two vertices (nodes) on a given graph, such that the sum of the weights on its constituent edges is minimized. This problem has been intensively investigated over years, due to its extensive applications in graph theory, artificial intelligence, computer network and the design of transportation systems. The classic Dijkstra’s algorithm was designed to solve the single source shortest path problem for a static graph. It works starting from the source node and calculating the shortest path on the whole network. Noting that an upper bound of the distance between two nodes can be evaluated in advance on the given transportation network.


Author(s):  
Raivis Gavars ◽  
Einārs Netlis-Galejs ◽  
Jānis Artūrs Lazdiņš ◽  
Ilmārs Kangro

The Floyd–Warshall algorithm is a good choice for computing paths between all pairs of vertices indense graphs, in which most or all pairs of vertices are connected by edges. For sparse graphs with non-negative edgeweights, a better choice is to use Dijkstra's algorithm from each possible starting vertex. Also, a very good thing is that thesolution is very accurate, when using a computer. In this paper, the authors tried to apply a solution using C++programming language to make possible many entries.


2020 ◽  
Author(s):  
Fredrik Ljunggren ◽  
Kristian Persson ◽  
Anders Peterson ◽  
Christiane Schmidt

Abstract We present an algorithm to insert a train path in an existing railway timetable close to operation, when we want to affect the existing (passenger) traffic as little as possible. Thus, we consider all other trains as fixed, and aim for a resulting train path that maximizes the bottleneck robustness, that is, a train path that maximizes the temporal distance to neighboring trains in the timetable. Our algorithm is based on a graph formulation of the problem and uses a variant of Dijkstra’s algorithm. We present an extensive experimental evaluation of our algorithm for the Swedish railway stretch from Malmö to Hallsberg. Moreover, we analyze the size of our constructed graph.


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