scholarly journals Efficient Processing of Moving Top-k Spatial Keyword Queries in Directed and Dynamic Road Networks

2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Muhammad Attique ◽  
Hyung-Ju Cho ◽  
Tae-Sun Chung
Keyword(s):  
Euclidean Space ◽  
Query Processing ◽  
Processing Time ◽  
Road Networks ◽  
Spatial Networks ◽  
Weight Changes ◽  
Traffic Conditions ◽  
Data Object ◽  
Efficient Processing ◽  
Dynamic Road Networks

A top-k spatial keyword (TkSk) query ranks objects based on the distance to the query location and textual relevance to the query keywords. Several solutions have been proposed for top-k spatial keyword queries. However, most of the studies focus on Euclidean space or only investigate the snapshot queries where both the query and data object are static. A few algorithms study TkSk queries in undirected road networks where each edge is undirected and the distance between two points is the length of the shortest path connecting them. However, TkSk queries have not been thoroughly investigated in directed and dynamic spatial networks where each edge has a particular orientation and its weight changes according to the traffic conditions. Therefore, in this study, we address this problem by presenting a new method, called COSK, for processing continuous top-k spatial keyword queries for moving queries in directed and dynamic road networks. We first propose an efficient framework to process snapshot TkSK queries. Furthermore, we propose a safe-exit-based approach to monitor the validity of the results for moving TkSK queries. Our experimental results demonstrate that COSK significantly outperforms existing techniques in terms of query processing time and communication cost.

scholarly journals Efficient Processing of All Nearest Neighbor Queries in Dynamic Road Networks

Mathematics ◽  
2021 ◽  
Vol 9 (10) ◽  
pp. 1137
Author(s):  
Aavash Bhandari ◽  
Aziz Hasanov ◽  
Muhammad Attique ◽  
Hyung-Ju Cho ◽  
Tae-Sun Chung
Keyword(s):  
Road Network ◽  
Nearest Neighbor ◽  
Computational Cost ◽  
Road Networks ◽  
Coherence Property ◽  
Traffic Conditions ◽  
Efficient Processing ◽  
Data Objects ◽  
Nearest Neighbor Queries ◽  
Dynamic Road Networks

The increasing trend of GPS-enabled smartphones has led to the tremendous usage of Location-Based Service applications. In the past few years, a significant amount of studies have been conducted to process All nearest neighbor (ANN) queries. An ANN query on a road network extracts and returns all the closest data objects for all query objects. Most of the existing studies on ANN queries are performed either in Euclidean space or static road networks. Moreover, combining the nearest neighbor query and join operation is an expensive procedure because it requires computing the distance between each pair of query objects and data objects. This study considers the problem of processing the ANN queries on a dynamic road network where the weight, i.e., the traveling distance and time varies due to various traffic conditions. To address this problem, a shared execution-based approach called standard clustered loop (SCL) is proposed that allows efficient processing of ANN queries on a dynamic road network. The key concept behind the shared execution technique is to exploit the coherence property of road networks by clustering objects that share common paths and processing the cluster as a single path. In an empirical study, the SCL method achieves significantly better performance than competitive methods and efficiently reduces the computational cost to process ANN queries in various problem settings.

scholarly journals Efficient Processing of Movingk-Range Nearest Neighbor Queries in Directed and Dynamic Spatial Networks

2016 ◽  
Vol 2016 ◽  
pp. 1-17 ◽  
Author(s):  
Hyung-Ju Cho ◽  
Rize Jin
Keyword(s):  
Location Privacy ◽  
Nearest Neighbor ◽  
Real Life ◽  
Location Based Services ◽  
Spatial Networks ◽  
Weight Changes ◽  
Server Side ◽  
Query Region ◽  
Efficient Processing ◽  
Nearest Neighbor Queries

Ak-range nearest neighbor (kRNN) query in a spatial network finds thekclosest objects to each point in the query region. The essential nature of thekRNN query is significant in location-based services (LBSs), where location-aware queries with query regions such askRNN queries are frequently used because of the issue of location privacy and the imprecision of the associated positioning techniques. Existing studies focus on reducing computation costs at the server side while processingkRNN queries. They also consider snapshot queries that are evaluated once and terminated, as opposed to moving queries that require constant updating of their results. However, little attention has been paid to evaluating movingkRNN queries in directed and dynamic spatial networks where every edge is directed and its weight changes in accordance with the traffic conditions. In this paper, we propose an efficient algorithm called MORAN that evaluates movingk-range nearest neighbor (MkRNN) queries in directed and dynamic spatial networks. The results of a simulation conducted using real-life roadmaps indicate that MORAN is more effective than a competitive method based on a shared execution approach.

Distributed shortest path query processing on dynamic road networks

2017 ◽  
Vol 26 (3) ◽  
pp. 399-419 ◽  
Author(s):  
Dongxiang Zhang ◽  
Dingyu Yang ◽  
Yuan Wang ◽  
Kian-Lee Tan ◽  
Jian Cao ◽  
...  
Keyword(s):  
Query Processing ◽  
Shortest Path ◽  
Road Networks ◽  
Shortest Path Query ◽  
Dynamic Road Networks

scholarly journals The Energy-Efficient Processing of Fine Materials by the Micropyretic Synthesis Route

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
H. P. Li
Keyword(s):  
Energy Efficient ◽  
Processing Time ◽  
Combustion Temperature ◽  
Processing Parameters ◽  
The Novel ◽  
Diffusion Controlled ◽  
Efficient Processing ◽  
The One ◽  
Processing Techniques ◽  
Diffusion Controlled Reaction

Energy-efficient processing of TiB compound with nanowhiskers by micropyretic synthesis is investigated in this paper. Micropyretic synthesis not only offers shorter processing time but also excludes the requirement for high-temperature sintering and it is considered as the one of the novel energy-saving processing techniques. Experimental study and numerical simulation are both carried out to investigate the correlation of the processing parameters on the microstructures of the micropyretically synthesized products. The diffusion-controlled reaction mechanism is proposed in this study. It is noted that nanosize TiB whiskers only occurred when the combustion temperature is lower than the melting point of TiB but higher than the extinguished temperature. The results generated in the numerical calculation can be used as a helpful reference to select the proper route of processing nanosize materials. The Arrhenius-type plot of size and temperature is used to calculate the activation energy of TiB reaction. In addition to verifying the accuracy of the experimental measures, the reaction temperature for producing the micropyretically synthesized products with nanofeatures can be predicted.

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