Keyword Search Mechanisms in Geo-Spatial Databases

2018 ◽  
pp. 176-194
Author(s):  
Priya M. ◽  
Kalpana R.
Keyword(s):  
Spatial Databases ◽  
Keyword Search ◽  
Database Systems ◽  
Index Structure ◽  
Hybrid Index ◽  
Spatial Objects ◽  
Ranking Model ◽  
Text Information ◽  
Spatial Indexes ◽  
The Given

Most web and mobile applications are based on searching the location-based objects called spatial objects. In spatial database systems, searching such objects is a challenging task since it deals with geo-spatial capabilities. Sometimes, the spatial queries are associated with text information in order to obtain the most relevant answers nearest to the given location. Such queries are called spatial textual query. Conventional spatial indexes and text indexes are not suitable for resolving such queries. Since these indexes use various approaches to perform searching, they can cause performance degradation. Effective processing of the query mainly depends on the index structure, searching algorithms, and location-based ranking. This chapter reviews the different hybrid index structures and search mechanisms to extract the spatial objects, the different ranking model it supports, and the performance characteristics.

scholarly journals Efficient Geo-Textual Hybrid Indexing Techniques for Moving Objects and Queries

2020 ◽  
Vol 8 (6) ◽  
pp. 4419-4428
Keyword(s):  
Moving Objects ◽  
Traffic Monitoring ◽  
Spatial Index ◽  
Index Structure ◽  
Maintenance Cost ◽  
Hybrid Index ◽  
Indexing Techniques ◽  
Inverted List ◽  
Textual Data ◽  
Future Position

Advancements of various Geographic Information Technologies have resulted in huge growth in Geo-Textual data. Many Indexing and searching algorithms are developed to handle this Geo-Textual data which contains spatial, textual and temporal information. In past, Indexing and searching algorithms are developed for the applications in which the object trajectory or velocity vector is known in advance and hence we can predict the future position of the objects. There are real time applications like emergency management systems, traffic monitoring, where the objects movements are unpredictable and hence future position of the objects cannot be predicted. Techniques are required to answer the geo-textual kNN query where the velocity vectors or trajectories of moving and moving queries are not known. In case of moving objects, capturing current position of the object and maintaining spatial index optimally is very much essential. The hybrid indexing techniques used earlier are based on R-tree spatial index. The nodes of the R-tree index structure are split or merged to maintain the locations of continuously moving objects, increasing the maintenance cost as compared to the grid index. In this paper a solution is proposed for creating and maintaining hybrid index for moving objects and queries based on grid and inverted list hybrid indexing techniques. The method is also proposed for finding Geo-Textual nearest neighbours for static and moving queries using hybrid index and conceptual partitioning of the grid. The overall gain reported by the experimental work using hybrid index over the non- hybrid index is 30 to 40 percent depending on the grid size chosen for mapping the data space and on the parameters of queries.

scholarly journals Enhancing Quad Tree for Spatial Index Using Space Filling Curves

2020 ◽  
Vol 38 (1B) ◽  
pp. 15-25
Author(s):  
Ali A. Hussain ◽  
Rehab F. Hassan
Keyword(s):  
Spatial Databases ◽  
Space Filling ◽  
Space Filling Curve ◽  
Effective Implementation ◽  
Quad Tree ◽  
Implementation Time ◽  
Spatial Indexes ◽  
Space Requirements ◽  
Filling Curve ◽  
And Storage

Spatial indexes, such as those based on the Quad Tree, are important in spatial databases for the effective implementation of queries with spatial constraints, especially when queries involve spatial links. The quaternary trees are a very interesting subject, given the fact that they give the ability to solve problems in a way that focuses only on the important areas with the highest density of information. Nevertheless, it is not without the disadvantages because the search process in the quad tree suffers from the problem of repetition when reaching the terminal node and return to the behavior of another way in the search and lead to the absorption of large amounts of time and storage. In this paper, the quad tree was improved by combining it with one of the space filling curve types, resulting in reduced storage space requirements and improved implementation time

Kansei Database and AR*-Tree for Speeding up the Retrieval

2010 ◽  
pp. 111-125 ◽  
Author(s):  
Yaokai Feng
Keyword(s):  
Information Retrieval ◽  
Key Words ◽  
Multimedia Retrieval ◽  
Index Structure ◽  
Multidimensional Indexing ◽  
General Flow ◽  
Retrieval Systems ◽  
Information Retrieval Systems ◽  
Speed Up ◽  
Text Information

Along with Kansei information being successfully introduced to information retrieval systems, particularly multimedia retrieval systems, many Kansei retrieval systems have been implemented in the past two decades. And, it has become clear that the traditional multimedia retrieval systems using key-words or/and other text information are not enough in many applications, because that they can not deal with sensitive words reflecting user’s subjectivity. In this chapter, Kansei retrieval systems efficiently taking user’s subjectivity into account will be discussed in detail. Like many traditional retrieval systems, Kansei retrieval systems are also based on databases system, which are called Kansei databases. After roughly introducing some existing Kansei retrieval systems is a general flow for designing Kansei retrieval systems. Also, we will discuss how to speed up the Kansei retrieval systems by using multidimensional indexing technologies and you will learn that our proposed multidimensional index structure, Adaptive R*-tree (AR*-tree for short), is more suitable to Kansei retrieval systems than the traditional multidimensional indexing technologies.

Heterogeneous placement optimization for database query processing

2017 ◽  
Vol 59 (3) ◽  
Author(s):  
Tomas Karnagel ◽  
Dirk Habich
Keyword(s):  
Query Processing ◽  
Database Systems ◽  
Improve Performance ◽  
Database Query ◽  
Placement Decisions ◽  
Placement Optimization ◽  
Database Query Processing ◽  
The Given

AbstractComputing hardware is constantly evolving and database systems need to adapt to ongoing hardware changes to improve performance. The current hardware trend is heterogeneity, where multiple computing units like CPUs and GPUs are used together in one system. In this paper, we summarize our efforts to use hardware heterogeneity efficiently for query processing. We discuss different approaches of execution and investigate heterogeneous placement in detail by showing, how to automatically determine operator placement decisions according to the given hardware environment and query properties.

scholarly journals Research to justify the perspective use of individual coordinate systems for contiguous objects modelling with the case study of Moscow Saints Petersburg railway

2021 ◽  
Vol 310 ◽  
pp. 06003
Author(s):  
Aleksei Portnov
Keyword(s):  
Railway Track ◽  
Building Information Modelling ◽  
Information Modelling ◽  
Spatial Objects ◽  
Digital Twins ◽  
Railway Infrastructure ◽  
Mercator Projection ◽  
Building Information ◽  
The Given

The science of cartography should provide a historical mission, that is navigation, and also meet modern agendas including significantly expanding opportunities for BIM technologies, integrating functions of GIS and CAD systems. In this regard, cartography should be considered a fundamental basis for modern trends while creating digital twins of spatial objects. The practical part of the provided experiments included data collecting aimed at Moscow Saints Petersburg railway infrastructure, the calculation of optimal parameters of the oblique Mercator projection in the Hotine version for the given object, and the construction of a 3D railway track model. This research investigated the principles of unique cartographic projections, strictly focused on the certain functioning objects. The research can helps many users and designers of digital twins of spatial objects pay their attention to the applied cartography specifics concerning these issues and also take into account the recommendations while creating Building Information Modelling (BIM) and Infrastructure Information Modelling (IIM) as well.

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