Access structures for fuzzy spatial queries

Sozer, A
Yazıcı, Adnan
Spatial data are complex and have spatial components and uncertain properties. It is important to develop effective spatial and aspatial indexing techniques to facilitate spatial and/or aspatial querying for databases that deal with spatial data. In this study we discuss a number of spatial index structures, such as Multi-level grid file (MLGF), R-tree, and R*-tree, for fuzzy spatial and/or aspatial queries.


Implementation of X-Tree with 3D Spatial Index and Fuzzy Secondary Index
Keskin, Sinan; Yazıcı, Adnan; Oğuztüzün, Mehmet Halit S. (2011-10-28)
In spatial databases, traditional approach is to build separate indexing structures for spatial and non-spatial attributes. This article introduces a new coupled approach that combines a 3D spatial primary index and a fuzzy non-spatial secondary index. Based on tests with several types of queries on a meteorological data set, it is shown that our coupled structure reduces the number of iterations and the time consumed for querying compared with the traditional uncoupled one.
Performance Comparison of Single and Dual Polarized MIMO Systems
Soker, Burak; Tuncer, Temel Engin (2013-04-26)
Polarization diversity in a 2x2 MIMO communication system is investigated for Alamouti and spatial multiplexing transmission schemes. Parameters such as cross polar discrimination and correlation coefficients introducing the polarization diversity are included in the channel model. Receive antenna correlation coefficients are generated from a realistic random model. The relative performance of the single and dual polarizations depends significantly on the channel characteristics. Single and dual polarizatio...
Indexing Fuzzy Spatiotemporal Data for Efficient Querying: A Meteorological Application
Sozer, Aziz; Yazıcı, Adnan; Oğuztüzün, Mehmet Halit S. (2015-10-01)
Spatiotemporal data, in particular fuzzy and complex spatial objects representing geographic entities and relations, is a topic of great importance in geographic information systems and environmental data management systems. For database researchers, modeling and designing a database of fuzzy spatiotemporal data and querying such a database efficiently have been challenging issues due to complex spatial features and uncertainty involved. This paper presents an integrated approach to modeling, indexing, and ...
A Comparison of spatial modulation and spatial multiplexing systems in multipath fading channels
Saygılı, Halil; Yılmaz, Ali Özgür; Department of Electrical and Electronics Engineering (2013)
In this thesis, multiple antenna transmission techniques like spatial multiplexing, spatial modulation and multiple active spatial modulation are compared in multipath fading channels. Maximum likelihood sequence estimation (MLSE) based on the Ungerboeck observation model is the optimal operation for intersymbol interference channels and applied on the mentioned multiple antenna transmission strategies. The performance analysis based on Monte Carlo simulations and comparison of the computational complexity ...
Semi-Bayesian Inference of Time Series Chain Graphical Models in Biological Networks
Farnoudkia, Hajar; Purutçuoğlu Gazi, Vilda (null; 2018-09-20)
The construction of biological networks via time-course datasets can be performed both deterministic models such as ordinary differential equations and stochastic models such as diffusion approximation. Between these two branches, the former has wider application since more data can be available. In this study, we particularly deal with the probabilistic approaches for the steady-state or deterministic description of the biological systems when the systems are observed though time. Hence, we consider time s...
Citation Formats
A. Sozer and A. Yazıcı, “Access structures for fuzzy spatial queries,” 2002, p. 383, Accessed: 00, 2020. [Online]. Available: