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**11 - 20**of**20**### Abstract SHARC: Fast and Robust Unidirectional Routing ∗

"... During the last years, impressive speed-up techniques for Dijkstra’s algorithm have been developed. Unfortunately, the most advanced techniques use bidirectional search which makes it hard to use them in scenarios where a backward search is prohibited. Even worse, such scenarios are widely spread, e ..."

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During the last years, impressive speed-up techniques for Dijkstra’s algorithm have been developed. Unfortunately, the most advanced techniques use bidirectional search which makes it hard to use them in scenarios where a backward search is prohibited. Even worse, such scenarios are widely spread, e.g., timetable-information systems or timedependent networks. In this work, we present a unidirectional speed-up technique which competes with bidirectional approaches. Moreover, we show how to exploit the advantage of unidirectional routing for fast exact queries in timetable information systems and for fast approximative queries in time-dependent scenarios. By running experiments on several inputs other than road networks, we show that our approach is very robust to the input. 1

### Contracting Timetable . . .

, 2008

"... During the last years, impressive progress has been achieved in the field of speed-up techniques for DIJKSTRA’s algorithm. Due to the availability of road networks, most speed-up techniques were developed for such networks. The fastest known techniques use contraction, a procedure that reduces the ..."

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During the last years, impressive progress has been achieved in the field of speed-up techniques for DIJKSTRA’s algorithm. Due to the availability of road networks, most speed-up techniques were developed for such networks. The fastest known techniques use contraction, a procedure that reduces the graph size, in order to gain their impressive speed-ups. However, in a recent work it was observed that those techniques yield a much worse performance when applied on time-expanded networks resulted from railway timetable information data, and conjectured that this might be due to the contraction routine. In this work, we present a new contraction routine tailored to time-expanded graphs representing railway timetable information. This is a first step towards the adaption and development of contraction-based speed-up techniques to these networks.

### GPU-based Computation of Distance Functions on Road Networks with Applications

"... We present a GPU-based algorithm for computing discretized distance functions on road networks. As applications, we provide algorithms for computing discrete Order-k Network Voronoi diagrams and for approximately solving k-Nearest Neighbor queries and Aggregate k-Nearest Neighbor queries on road net ..."

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We present a GPU-based algorithm for computing discretized distance functions on road networks. As applications, we provide algorithms for computing discrete Order-k Network Voronoi diagrams and for approximately solving k-Nearest Neighbor queries and Aggregate k-Nearest Neighbor queries on road networks. Finally, we present experimental results obtained with the implementation of our algorithms.

### JOURNAL OF BIOMEDICAL SEMANTICS

"... A framework for ontology-based question answering with application to parasite immunology ..."

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A framework for ontology-based question answering with application to parasite immunology

### A RDBMS based Framework for Shortest Path Discovery with Constraint Paths

"... Nowadays, graphs are used in many applications and the graph size is rapidly increasing. The shortest path discovery considering constraint conditions is very important. For example, when a road is temporarily not available, paths not including the invalid road are required. In this paper, we propos ..."

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Nowadays, graphs are used in many applications and the graph size is rapidly increasing. The shortest path discovery considering constraint conditions is very important. For example, when a road is temporarily not available, paths not including the invalid road are required. In this paper, we propose an efficient RDBMS based shortest path discovery method considering constraint conditions in a large graph. The proposed method finds the shortest path not containing the constraint path by avoiding expanding the paths including the given constraint path. We propose a novel approach that expands strategy by using the index table proposed by the FEM framework. We also propose an optimizing method for multiple constraint paths. We experimentally verify that our approaches can achieve high space and time efficiency in a large graph.

### Raghavan Raman Oracle Labs

"... The problem of efficiently analyzing graphs of various shapes and sizes has been recently enjoying an increased level of at-tention both in the academia and in the industry. This trend prompted creation of specialized graph databases that have been rapidly gaining popularity of late. In this paper w ..."

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The problem of efficiently analyzing graphs of various shapes and sizes has been recently enjoying an increased level of at-tention both in the academia and in the industry. This trend prompted creation of specialized graph databases that have been rapidly gaining popularity of late. In this paper we ar-gue that there exist alternatives to graph databases, provid-ing competitive or superior performance, that do not require replacement of the entire existing storage infrastructure by the companies wishing to deploy them. 1.

### A Landmark Algorithm for the Time-dependent . . .

, 2008

"... The shortest path problem is one of the most classical problem in combinatorial optimization problem which, given an edge-weighted graph and two vertices, asks to find a path between the two vertices of the minimum length. In this thesis, we consider a generalization of the shortest path problem in ..."

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The shortest path problem is one of the most classical problem in combinatorial optimization problem which, given an edge-weighted graph and two vertices, asks to find a path between the two vertices of the minimum length. In this thesis, we consider a generalization of the shortest path problem in which the edge length is time-variable, which we call the time-dependent shortest path problem. This kind

### Performance Analysis . . . for Shortest Path Queries in Networks of Random and Planar Types

, 2012

"... The essential elements of any network application system uses shortest‐path algorithm mostly for problems of network namely routing, viz. When seen in the light of the basic requirement of such a system, to provide high quality path identification or routing solutions fast, algorithms have to be eff ..."

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The essential elements of any network application system uses shortest‐path algorithm mostly for problems of network namely routing, viz. When seen in the light of the basic requirement of such a system, to provide high quality path identification or routing solutions fast, algorithms have to be efficient. There are many speedup techniques and combined speedup techniques available which find shortest path efficiently in networks. Also parallelization is incorporated in some of the speedup techniques, where the performance is monitored in multicore processors. This paper deals with comparison of parallelized speedup techniques with sequential version of the same and finding performance improvement achieved in parallelized speedup techniques with respect to runtime and number of vertices visited during shortest path computation. The techniques were tested in random and planar types of graph networks, which may be suitable for networks of the same type. Performance of parallelization has good impact of speedup in random graph type of networks(45 % to 90 % with respect to runtime and 25 % to 830 % with respect to vertices visited) than planar graph type of networks.