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Exact Solutions of Fisher and Generalized Fisher Equations with Variable Coefficients

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Acta Mathematicae Applicatae Sinica 2007年第4期23卷 563-568页

作者： arzu ■ün Cevat Kart Department of Mathematics Faculty of SciencesAnkara University06100 Tando■an-Ankara Turkey

In this work, we consider a Fisher and generalized Fisher equations with variable coefficients. Using truncated Painleve expansions of these equations, we obtain exact solutions of these equations with a constraint on... 详细信息

关键词： nonlinear evolution equations fisher equation generalized fisher equation backlund transformation painleve property

Fixing an illusion–an empirical assessment of correction methods for the terrain reversal effect in satellite images

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International Journal of Digital Earth 2020年第10期13卷 1135-1150页

作者： Gianna Hartung arzu Çöltekin Department of Geography University of ZurichZurichSwitzerland FHnW University of Applied Sciences and Arts northwestern ZurichSwitzerland

Identifying land forms and land cover classes are important tasks in image ***,a phenomenon called terrain reversal effect(TRE)causes an inverted perception of 3D *** this inversion occurs,valleys appear as ridges and vice *** the TRE can severely impair the ability to identify 3D land forms,‘correcting’for the TRE in imagery can introduce new ***,one of most commonly-proposed methods–shaded relief map(SRM)overlay–appears to impair the ability to identify land cover *** this paper,we report a comparative empirical evaluation of an SRM overlay solution,and its‘enhanced’versions supported by various other cues(stereopsis,motion,labels).In response to the different solutions,we measure the effectiveness,efficiency,confidence and preferences of our participants in land form and land cover identification *** examined methods significantly improve the ability to detect land forms accurately,but they also impair the ability to identify the land cover classes to different ***,participants’visualization preferences contradict their performance with them,calling for reflection on the visual effects of the applied correction *** on the study,recommendations concerning the correction of the TRE are drawn,and gaps are identified.

关键词： Terrain reversal effect satellite images correction methods shaded relief map stereoscopy motion

Comparing the terrain reversal effect in satellite images and in shaded relief maps:an examination of the effects of color and texture on 3D shape perception from shading

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International Journal of Digital Earth 2019年第4期12卷 442-459页

作者： arzu Çöltekin Julien Biland Department of Geography University of ZurichZurichSwitzerland Department of Geography University of BernBernSwitzerland

Terrain reversal effect(TRE)causes reversed 3D shape perception in satellite images and shaded relief maps(SRMs),and introduces difficulties in identifying landforms such as valleys and *** this paper,in a controlled laboratory experiment,we compare how well 27 participants could identify valleys and ridges over 33 locations using SRMs,color satellite images and grayscale satellite *** main depth cue is shadow both in vertical-view images and ***,the presence of texture and color in images also affect 3D shape *** our participants experience the illusion strongly:with the SRMs,it is very severe(2%accuracy),with grayscale images low but considerably better than SRMs(17.6%accuracy),and slightly worse with color imagery(15.3%accuracy).These differences between SRMs and imagery suggest that the participants who are able to bypass the illusion consciously or subconsciously interpret the photographic *** support this observation further with a cue-strength ***,we provide exploratory analyses of the effects of expertise,global convexity bias,and bistable *** original empirical observations serve towards a better understanding of this visual illusion,and contribute towards nuanced and appropriate solutions to correcting for TRE differently for satellite images and SRMs.

关键词： Terrain reversal relief inversion false topographic perception phenomenon photo interpretation visual illusion user study bistable perception global convexity bias

In vitro antibacterial and antitumor activities of some medicinal plant extracts, growing in Turkey

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Asian Pacific Journal of Tropical Medicine 2013年第8期6卷 616-624页

作者： arzu Birinci Yildirim Fatma Pehlivan Karakas arzu Ucar Turker Department of Biology Abant Izzet Baysal University

Objective: To investigate antibacterial and antitumor activities of 51 different extracts prepared with 3 types of solvents (water, ethanol and methanol) of 16 different plant species (Ajuga reptans (A. reptans) L., Phlomis pungens (P. pungens) Willd., Marrubium astracanicum (M. astracanicum) Jacq., nepeta nuda (n. nuda) L., Stachys annua (S. annua) L., Genista lydia (G. lydia) Boiss., nuphar lutea (n. lutea) L., nymphaea alba (n. alba) L., Vinca minor (V. minor) L., Stellaria media (S. media) L., Capsella bursa-pastoris (C. bursa-pastoris) L., Galium spurium (G. spurium) L., Onosma heterophyllum (O. heterophyllum) Griseb., Reseda luteola (R. luteola) L., Viburnum lantana (V. lantana) L. and Mercurialis annua (M. annua) L.) grown in Turkey was conducted. Methods: Antibacterial activity was evaluated with 10 bacteria including Streptococcus pyogenes (S. pyogenes), Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis), Escheria coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Salmonella typhimurium (S. typhimurium), Serratia marcescens (S. marcescens), Proteus vulgaris (P. vulgaris), Enterobacter cloacae (E. cloacea), and Klebsiella pneumoniae (K. pneumoniae) by using disc diffusion method. Antitumor activity was evaluated with Agrobacterium tumefaciens (A. tumefaciens)-induced potato disc tumor assay. Results: Best antibacterial activity was obtained with ethanolic extract of P. pungens against S. pyogenes . Ethanolic and methanolic extract of n. alba and ethanolic extract of G. lydia also showed strong antibacterial activities. Results indicated that alcoholic extracts especially ethanolic extracts exhibited strong antibacterial activity against both gram-positive and gram-negative bacteria. Best antitumor activity was obtained with methanolic extracts of n. alba and V. lantana (100% tumor inhibition). Ethanolic extract of n. alba , alcoholic extracts of n. lutea , A. reptans and V. minor flowers, methanolic extracts of G. lydia and O

关键词： Bioassays Antibacterial Antitumor Medicinal plants

Mathematical Modelling and 3D FEM Analysis of the Influence of Initial Stresses on the ERR in a Band Crack’s Front in the Rectangular Orthotropic Thick Plate

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Computers, Materials & Continua 2017年第3期53卷 249-270页

作者： arzu Turan Dincel Surkay DAkbarov Yildiz Technical University Department of Mathematical EngineeringDavutpasa Campus34220EsenlerIstanbul-Turkey Yildiz Technical University Faculty of Mechanical EngineeringDepartment of Mechanical EngineeringYildiz Campus34349BesiktasIstanbul-Turkey Institute of Mathematics and Mechanics of the national Academy of Science of Azerbaijan 37041BakuAzerbaijan

This paper deals with the mathematical modelling and 3D FEM study of the energy release rate(ERR)in the band crack’s front contained in the orthotropic thick rectangular plate which is stretched or compressed initially before the loading of the crack's edge *** initial stretching or compressing of the plate causes uniformly distributed normal stress to appear acting in the direction which is parallel to the plane on which the band crack is *** the appearance of the initial stress in the plate it is assumed that the crack's edge planes are loaded with additional uniformly distributed normal forces and the ERR caused with this additional loading is *** corresponding boundary value problem is formulated within the scope of the so-called 3D linearized theory of elasticity which allows the initial stress on the values of the ERR to be taken into *** results on the influence of the initial stress,anisotropy properties of the plate material,the crack’s length and its distance from the face planes of the plate on the values of the ERR,are presented and *** particular,it is established that for the relatively greater length of the crack’s band,the initial stretching of the plate causes a decrease,but the initial compression causes an increase in the values of the ERR.

关键词： Band crack energy release rate stress intensity factor initial stress orthotropic material rectangular plate 3D FEM

Study for obtaining the exact solutions for the propagation of pulses in optical fibers

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Communications in Theoretical Physics 2024年第10期76卷 12-23页

作者： arzu Akbulut Waseem Razzaq Filiz Tascan Department of Mathematics Faculty of Arts and ScienceBursa Uludağ UniversityBursaTürkiye Math Center House no 87 Rahmanyia ColonyVehariPakistan Department of Mathematics and Computer Sciences Faculty of Arts and ScienceEskisehir Osmangazi UniversityEskisehirTürkiye

In this study, the exact solutions for the propagation of pulses in optical fibers are *** values are given in the model used, and two nonlinear differential equations are *** equations are reduced to ordinary differential equations with the help of wave transformations. Then, the obtained differential equations are solved by two different methods,namely the modified simplest equation and the modified Kudryashov procedures. The solutions are given by hyperbolic, trigonometric and rational functions and the results are useful for optics,engineering and other related areas. Finally three-dimensional, contour and two-dimensional shapes are given for some solutions. These figures are important for understanding the motion of the wave. The given methods are applied to the equations for the first time. To the best of the authors' knowledge, these results are new and have not been obtained in the literature. The results are useful for applied mathematics, physics and other related areas.

关键词： traveling wave transformation exact solutions the modified simplest equation procedure

Prevalence of the terrain reversal effect in satellite imagery

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International Journal of Digital Earth 2015年第8期8卷 640-655页

作者： Miguel-Angel Bernabé-Poveda arzu Çöltekin Universidad de las Fuerzas Armadas–ESPE Departamento de Ciencias de la Tierra y de la ConstrucciónSangolquíPichinchaEcuador Geographic Information Visualization and Analysis Group Department of GeographyUniversity of ZurichSwitzerland

The terrain reversal effect is a perceptual phenomenon which causes an illusion in various 3D geographic visualizations where landforms appear inverted,*** perceive valleys as ridges and vice *** that such displays are important for spatio-visual analysis,this illusion can lead to critical mistakes in interpreting the ***,it is currently undocumented how commonly this effect is *** this paper,we study the prevalence of the terrain reversal effect in satellite imagery through a two-stage online user *** experiment was conducted with the participation of a diverse and relatively large population(n=535).Participants were asked to identify landforms(valley or ridge?)or judge a 3D spatial relationship(is A higher than B?).When the images were rotated by 180°,the results were *** a control task with‘illusion-free’original images,people were successful in identifying landforms,yet a very strong illusion occurred when these images were rotated 180°.Our findings demonstrate that the illusion is acutely present;thus,we need a better understanding of the problem and its ***,the results caution us that in an interactive environment where people can rotate the display,we might be introducing a severe perceptual problem.

关键词： terrain reversal relief inversion false topographic perception phenomenon photo interpretation visual illusion user study

Solving Space-Time Fractional Differential Equations by Using Modified Simple Equation Method

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Communications in Theoretical Physics 2016年第5期65卷 563-568页

作者： Melike Kaplan arzu Akbulut Ahmet Bekir Eskisehir Osmangazi University Art-Science Faculty Department of Mathematics-Computer

In this article,we establish new and more general traveling wave solutions of space-time fractional Klein–Gordon equation with quadratic nonlinearity and the space-time fractional breaking soliton equations using the modified simple equation *** proposed method is so powerful and effective to solve nonlinear space-time fractional differential equations by with modified Riemann–Liouville derivative.

关键词： symbolic computation exact solution space-time fractional differential equation space-time fractional Klein–Gordon equation the space-time fractional breaking soliton equations

Toward optimizing the design of virtual environments for route learning:empirically assessing the effects of changing levels of realism on memory

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International Journal of Digital Earth 2019年第2期12卷 137-155页

作者： Ismini E.Lokka arzu Çöltekin Department of Geography University of ZurichZurichSwitzerland

Broadly,this paper is about designing memorable 3D geovisualizations for spatial knowledge acquisition during(virtual)*** is a fundamentally important task,and even though most people navigate every day,many find it difficult in unfamiliar *** people get lost in an unfamiliar environment,or are unable to remember a route that they took,they might feel anxiety,disappointment and frustration;and in real world,such incidents can be costly,and at times,***,in this paper,we study the design decisions in terms of visual realism in a city model,propose a visualization design optimized for route learning,implement and empirically evaluate this *** evaluation features a navigational route learning task,where we measure shortand long-term recall accuracy of 42 participants with varying spatial abilities and memory *** findings provide unique empirical evidence on how design choices affect memory in route learning with geovirtual environments,contributing toward empirically verified design guidelines for digital cities.

关键词： 3D representation digital city digital earth virtual reality visualization