Browsing by Subject "Symmetry"

Now showing 1 - 9 of 9

Open Access
BilKristal 2.0: a tool for pattern information extraction from crystal structures
(Elsevier BV, 2014-01) Okuyan, E.; Güdükbay, Uğur
We present a revised version of the BilKristal tool of Okuyan et al. (2007). We converted the development environment into Microsoft Visual Studio 2005 in order to resolve compatibility issues. We added multi-core CPU support and improvements are made to graphics functions in order to improve performance. Discovered bugs are fixed and exporting functionality to a material visualization tool is added.
Open Access
BilKristal 4.0: A tool for crystal parameters extraction and defect quantification
(Elsevier, 2015) Okuyan, E.; Okuyan, C.
In this paper, we present a revised version of BilKristal 3.0 tool. Raycast screenshot functionality is added to provide improved visual analysis. We added atomic distance analysis functionality to assess crystalline defects. We improved visualization capabilities by adding high level cut function definitions. Discovered bugs are fixed and small performance optimizations are made. © 2015 Elsevier B.V. All rights reserved.
Open Access
Entanglement and its operational measure
(Springer, 2006) Klyachko, Alexander A.; Öztop, Barış; Shumovsky, Alexander S.
An operational representation of concurrence measuring the entanglement of bipartite systems by means of averages of basic observables is discussed. We prove the validity of this representation for bipartite systems with any dimension of a single-party Hilbert space. We show that Wigner-Yanase "skew" information gives a reasonable estimation of the amount of entanglement (in ebits) carried by mixed two-qubit states.
Open Access
Pattern information extraction from crystal structures
(2005) Okuyan, Erhan
Determining crystal structure parameters of a material is a quite important issue in crystallography. Knowing the crystal structure parameters helps to understand physical behavior of material. For complex structures, particularly for materials which also contain local symmetry as well as global symmetry, obtaining crystal parameters can be quite hard. This work provides a tool that will extract crystal parameters such as primitive vectors, basis vectors and space group from atomic coordinates of crystal structures. A visualization tool for examining crystals is also provided. Accordingly, this work presents a useful tool that help crystallographers, chemists and material scientists to analyze crystal structures efficiently.
Open Access
Pattern information extraction from crystal structures
(Elsevier BV, 2007) Okuyan, E.; Güdükbay, Uğur; Gülseren, O.
Determining the crystal structure parameters of a material is an important issue in crystallography and material science. Knowing the crystal structure parameters helps in understanding the physical behavior of material. It can be difficult to obtain crystal parameters for complex structures, particularly those materials that show local symmetry as well as global symmetry. This work provides a tool that extracts crystal parameters such as primitive vectors, basis vectors and space groups from the atomic coordinates of crystal structures. A visualization tool for examining crystals is also provided. Accordingly, this work could help crystallographers, chemists and material scientists to analyze crystal structures efficiently. Program summary: Title of program: BilKristal. Catalogue identifier: ADYU_v1_0. Program summary URL: http://cpc.cs.qub.ac.uk/summaries/ADYU_v1_0. Program obtainable from: CPC Program Library, Queen's University of Belfast, N. Ireland. Licensing provisions: None. Programming language used: C, C++, Microsoft .NET Framework 1.1 and OpenGL Libraries. Computer: Personal Computers with Windows operating system. Operating system: Windows XP Professional. RAM: 20-60 MB. No. of lines in distributed program, including test data, etc.:899 779. No. of bytes in distributed program, including test date, etc.:9 271 521. Distribution format:tar.gz. External routines/libraries: Microsoft .NET Framework 1.1. For visualization tool, graphics card driver should also support OpenGL. Nature of problem: Determining crystal structure parameters of a material is a quite important issue in crystallography. Knowing the crystal structure parameters helps to understand physical behavior of material. For complex structures, particularly, for materials which also contain local symmetry as well as global symmetry, obtaining crystal parameters can be quite hard. Solution method: The tool extracts crystal parameters such as primitive vectors, basis vectors and identify the space group from atomic coordinates of crystal structures. Restrictions: Assumptions are explained in the paper. However, none of them can be considered as a restriction onto the complexity of the problem. Running time: All the examples presented in the paper take less than 30 seconds on a 2.4 GHz Pentium 4 computer. © 2007 Elsevier B.V. All rights reserved.
Open Access
Stable symmetries of plane sextics
(Springer Netherlands, 2008) Degtyarev, A.
We classify projective symmetries of irreducible plane sextics with simple singularities which are stable under equivariant deformations. We also outline a connection between order 2 stable symmetries and maximal trigonal curves. © 2008 Springer Science+Business Media B.V.
Open Access
Süslemede simetrinin etkisi
(Gazi Eğitim Fakültesi, 2016) Aktaş, M.; Aktaş, S.; Aktaş, B. K.; Aktaş, Burcu
Süsleme (tessellation); latince tessela (antik Roma mozaiklerinde kullanılan küçük fayans yada köşeli taşa verilen ad) kelimesinden gelmektedir. Britton, Seymor (1989) çalışmasında, süsleme, bir ya da daha fazla biçimde yapılmış, hiç boşluk kalmadan ve çakışma olmadan yüzeyi tamamen kaplayan bir desen olarak tanımlanmış, süslemeler iki boyutlu veya üç boyutlu da olabileceğini ve üç boyutlu süslemeler boşluğu kaplar iken iki boyutlu süslemeler yüzeyi kapladığını ifade etmişlerdir. Süsleme yapılırken farklı teknikler kullanılmaktadır. Bu tekniklerin içinde simetri çeşitlerinin kullanıldığı görülmektedir. Simetri; sanatçıların, mimarların ve bilim adamlarının bir çalışmadaki ahenkli düzeninde, bir heykelde, bir yapıda veya kristaller gibi doğa harikalarında ya da bitki, hayvan formlarında görülmektedir. Matematiğin bütününe bakıldığında da birçok alanda simetri kavramıyla karşılaşmak mümkündür. Field, Golubitsky (2009)'e göre simetri bir yaklaşımdır. Bu çalışmada orijinal çizimler kullanılarak; simetrinin çeşitleri, süsleme tekniklerinin (simetri çeşitleri ile) örnekleri verilmiş, simetri çeşitleri ile örüntü oluşturulup teknikleri nasıl uygulanacağı süslemenin nasıl oluşturulabileceği gösterilmiştir. Bu çalışma ile simetri ve süsleme sanatına yeni bir bakış getirilmiş olup ilgili literatüre yeni bir katkıda da bulunulmuştur.
Open Access
A tool for pattern information extraction and defect quantification from crystal structures
(Elsevier, 2015) Okuyan, E.; Okuyan, E.
In this paper, we present a revised version of BilKristal 2.0 tool. We added defect quantification functionality to assess crystalline defects. We improved visualization capabilities by adding transparency support and runtime visibility sorting. Discovered bugs are fixed and small performance optimizations are made. New version program summary Program title: BilKristal 3.0 Catalogue identifier: ADYU-v3-0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADYU-v3-0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 1868 923 No. of bytes in distributed program, including test data, etc.: 8854 507 Distribution format: tar.gz Programming language: C, C++, Microsoft.NET Framework 2.0 and OpenGL Libraries. Computer: Personal Computers with Windows operating system. Operating system: Windows XP or higher. RAM: 20-60 Megabytes. Classification: 8. Catalogue identifier of previous version: ADYU-v2-0 Journal reference of previous version: Comput. Phys. Comm. 185 (2014) 442 External routines: Microsoft.NET Framework 2.0. For the visualization tool, graphics card driver should also support OpenGL. Does the new version supersede the previous version?: Yes Nature of problem: Determining the crystal structure parameters of a material is a very important issue in crystallography. Knowing the crystal structure parameters helps the understanding of the physical behavior of material. For complex structures, particularly for materials which also contain local symmetry as well as global symmetry, obtaining crystal parameters can be very hard. Solution method: The tool extracts crystal parameters such as primitive vectors, basis vectors and identifies the space group from atomic coordinates of crystal structures. Reasons for new version: Additional features, Compatibility issues with newer development environments, Performance optimizations, Minor bug corrections. Summary of revisions:Defect quantification capability is added. The tool can process the imperfect crystal structures, finds and quantifies the crystalline defects. The tool is capable of finding positional defects, vacancy defects, substitutional impurities and interstitial impurities. The algorithms presented in [3] are used for defect quantification implementation.Transparency support is added to the visualization tool. Users are now allowed to set the transparency of each atom type individually.Runtime visibility sorting functionality is added to facilitate correct transparency computations.Visual Studio 2012 support is added. Visual Studio 2012 specific project files are created and the project is tested with this development environment.In visualization tool, an unused log file was created. This issue is corrected.In visualization tool, some OpenGL calls which are executed at every draw are changed to be executed only when they are needed, improving the visualization performance.Restrictions: Assumptions are explained in [1,2]. However, none of them can be considered as a restriction onto the complexity of the problem. Running time: The tool was able to process input files with more than a million atoms in less than 20 s on a PC with an Athlon quad-core CPU at 3.2 GHz using the default parameter values. References: [1] Erhan Okuyan, Ugur Güdükbay, Oguz Gülseren, Pattern information extraction from crystal structures, Comput. Phys. Comm. 176 (2007) 486. [2] Erhan Okuyan, Ugur Güdükbay, BilKristal 2.0: A tool for pattern information extraction from crystal structures, Comput. Phys. Comm. 185 (2014) 442. [3] Erhan Okuyan, Ugur Güdükbay, Ceyhun Bulutay, Karl-Heinz Heinig, MaterialVis: material visualization tool using direct volume and surface rendering techniques, J. Mol. Graphics Model. 50201450-60. © 2014 The Authors.
Open Access
Wayfinding in an unfamiliar environment: different spatial settings of two polyclinics
(SAGE, 2004-11) Baskaya, A.; Wilson, C.; Ozcan, Y. Z.
The purpose of this article is to explore spatial orientation and wayfinding behavior of newcomers in an unfamiliar environment and to emphasize the importance of landmarks and spatial differentiation in the acquisition of environmental knowledge. One setting with a symmetrical layout and regularly organized, monotonous units on different floors and another setting with an asymmetrical layout and repetitive units along one side of a linear corridor of one floor were used to explore different strategies for learning about large-scale spatial environments. Wayfinding performance was found to correlate with performances in sketch-map tasks and the answers of a questionnaire about each building. Most of the participants of the asymmetrical setting could complete a sketch map with a minimum of errors. In the symmetrical setting, however, some participants drew incomplete sketch maps but could find their way through the building with a minimum of errors.