Improved viewshed analysis algorithms for avionics applications

Özkıdık, Mustafa
Viewshed analysis is a common GIS capability used in various domains with various requirements. In avionics, viewshed analysis is a part of accuracy critical applications and the real time operating systems in embedded devices use preemptive scheduling algorithms to satisfy performance requirements. Therefore, to effectively benefit from the viewshed analysis, a method should be both fast and accurate. Although R3 algorithm is accepted as an accuracy benchmark, R2 algorithm with lower accuracy is preferred in many cases due to its better execution time performance. This thesis prioritizes accuracy and presents an alternative approach to improve execution time performance of the R3 algorithm. Considering different execution environments, improved versions of R3 are implemented for CPU and GPU. The experiment results show that CPU implementation of improved algorithms achieve 1.23x to 13.51x speedup depending on the observer altitude, range and topology of the terrain. In GPU implementation experiments up to 2.27x speedup is recorded. In addition to execution time performance improvements, the analysis results prove that proposed algorithms are capable of providing higher accuracy like R3.


Weighted multi-visibility analysis on directional paths
Şeker, Çağıl; Toprak, Vedat; Department of Geodetic and Geographical Information Technologies (2010)
Visibility analysis is an important GIS tool that is used in a diverse array of disciplines ranging from earth sciences to telecommunications. Multi-visibility, as a cumulative type of visibility, combines many point-to-point results into a multi-value array. Points, lines, or areas can be used as sources or targets; and the combined values can be calculated in both ways. Through multi-visibility, a special 2.5D visibility value surface can be constructed over a digital elevation model. The effectiveness of...
On Fuzzy Extensions to Energy Ontologies for Text Processing Applications
Kucuk, Dilek; Kucuk, Dogan; Yazıcı, Adnan (2014-10-28)
Ubiquitous application areas of domain ontologies include text processing applications like categorizing related documents of the domain, extraction of information from these documents, and semantic search. In this paper, we focus on the utilization of two energy ontologies, one for electrical power quality and the second for wind energy, within such applications. For this purpose, we present fuzzy extensions to these domain ontologies as fuzziness is an essential feature of the ultimate forms of the ontolo...
Acceleration of line of sight analysis algorithms with parallel programming
Yılmaz, Gökhan; Sürer, Elif; Temizel, Alptekin (null; 2017-11-23)
Line of sight (LOS) analysis is a set of methods and algorithms to determine the visible points in a terrain with reference to a specific observer point. This analysis is used in simulations, Geographic Information System (GIS) applications and games. For this reason, it is important to have a capability to get results quickly and facilitate analysis in such a way that the interaction with the changing reference points is possible. Van Kreveld, R2 and R3 are the most frequently used algorithms in line of si...
Development of GIS-based national hydrography dataset, sub-basin boundaries, and water quality/quantity data analysis system for Turkey
Girgin, Serkan; Usul, Nurünnisa; Akyürek, Zuhal; Department of Geodetic and Geographical Information Technologies (2003)
Computerized data visualization and analysis tools, especially Geographic Information Systems (GIS), constitute an important part of today̕s water resources development and management studies. In order to obtain satisfactory results from such tools, accurate and comprehensive hydrography datasets are needed that include both spatial and hydrologic information on surface water resources and watersheds. If present, such datasets may support many applications, such as hydrologic and environmental modeling, imp...
Automated integration of real-time and non-real-time defense systems
Dalkiran, Emre; Onel, Tolga; Oğuztüzün, Mehmet Halit S.; Demir, Kadir Alpaslan (2021-04-01)
Various application domains require the integration of distributed real-time or near-real-time systems with non-real-time systems. Smart cities, smart homes, ambient intelligent systems, or network-centric defense systems are among these application domains. Data Distribution Service (DDS) is a communi-cation mechanism based on Data-Centric Publish-Subscribe (DCPS) model. It is used for distributed systems with real-time operational constraints. Java Message Service (JMS) is a messaging standard for enterpr...
Citation Formats
M. Özkıdık, “Improved viewshed analysis algorithms for avionics applications,” Thesis (M.S.) -- Graduate School of Informatics. Information Systems., Middle East Technical University, 2019.