WoS
Permanent URI for this collectionhttps://hdl.handle.net/20.500.14411/18
Browse
65 results
Search Results
Article Citation - WoS: 10Citation - Scopus: 10Av Bitsadze's Observation on Bianalytic Functions and the Schwarz Problem(Taylor & Francis Ltd, 2018-08-14) Aksoy, Umit; Begehr, Heinrich; Celebi, A. OkayAccording to an observation of A.V. Bitsadze from 1948 the Dirichlet problem for bianalytic functions is ill-posed. A natural boundary condition for the polyanalytic operator, however, is the Schwarz condition. An integral representation for the solutions in the unit disc to the inhomogeneous polyanalytic equation satisfying Schwarz boundary conditions is known. This representation is extended here to any simply connected plane domain having a harmonic Green function. Some other boundary value problems are investigated with some Dirichlet and Neumann conditions illuminating that just the Schwarz problem is a natural boundary condition for the Bitsadze operator.Article Citation - WoS: 60Citation - Scopus: 64Seeding the Initial Population With Feasible Solutions in Metaheuristic Optimization of Steel Trusses(Taylor & Francis Ltd, 2017-02-10) Azad, Saeid Kazemzadeh; Kazemzadeh Azad, SaeidIn spite of considerable research work on the development of efficient algorithms for discrete sizing optimization of steel truss structures, only a few studies have addressed non-algorithmic issues affecting the general performance of algorithms. For instance, an important question is whether starting the design optimization from a feasible solution is fruitful or not. This study is an attempt to investigate the effect of seeding the initial population with feasible solutions on the general performance of metaheuristic techniques. To this end, the sensitivity of recently proposed metaheuristic algorithms to the feasibility of initial candidate designs is evaluated through practical discrete sizing of real-size steel truss structures. The numerical experiments indicate that seeding the initial population with feasible solutions can improve the computational efficiency of metaheuristic structural optimization algorithms, especially in the early stages of the optimization. This paves the way for efficient metaheuristic optimization of large-scale structural systems.Article Citation - WoS: 67Citation - Scopus: 74The Intuitionistic Fuzzy Electre Model(Taylor & Francis Ltd, 2017-09-05) Rouyendegh (Babek Erdebilli), Babak Daneshvar; Rouyendegh , Babak DaneshvarThe purpose of this research is to postulate and define a new model for Multi-Criteria DecisionMaking (MCDM) problems utilizing the Intuitionistic Fuzzy ELimination Et Choix Traduisant la REalite (IFELECTRE) method, otherwise identified as the Intuitionistic Fuzzy Index of Hesitation Degree method. The Intuitionistic Fuzzy Sets (IFS) method offers certain advantages in using vagueness over a Fuzzy Set (FS): the IFELECTRE method is used to handle more complicated problems, whereas the Decision-Makers (DMs) have some vagueness in assigning option values to the objects considered. The processes of evaluating qualitative and quantitative scales are combined in this work and the proposed model enables different DMs to assess and use IFS. The original ELECTRE method cannot be operated effectively owing to a lack of precise information under different conditions.Article Citation - WoS: 8Citation - Scopus: 7Does the Angulation of the Mandibular Third Molar Influence the Fragility of the Mandibular Angle After Trauma To the Mandibular Body? a Three-Dimensional Finite-Element Study(Taylor & Francis Ltd, 2018-05-19) Kilinc, Yeliz; Zor, Zeynep Fatma; Tumer, Mehmet Kemal; Erkmen, Erkan; Kurt, AhmetThe relationship between mandibular third molar (M3) angulation and mandibular angle fragility is not well established. The aim of this study was to evaluate the impact of M3 angulation on the mandibular angle fragility when submitted to a trauma to the mandibular body region. A three-dimensional (3D) mandibular model without M3 (Model 0) was obtained by means of finite-element analysis (FEA). Four models were generated from the initial model, representing distoangular (Model D), horizontal (Model H), mesioangular (Model M) and vertical (Model V) angulations. A blunt trauma with a magnitude of 2000 N was applied perpendicularly to the sagittal plane in the mandibular body. Maximum principal stress (P-max) (tensile stress) values were calculated in the bone. The lowest P-max stress values were noted in Model 0. When the M3 was present extra stress fields were found around marginal bone of second molar and M3. Comparative analysis of the models with M3 revealed that the highest level of stress was found in Model V, whereas Model D showed the lowest stress values. The angulation of M3 affects the stress levels in the mandibular angle and has an impact on mandibular fragility. The mandibular angle becomes more fragile in case of vertical impaction when submitted to a trauma to the mandibular body region.Article Citation - WoS: 26Citation - Scopus: 28Insights From Surgeons' Eye-Movement Data in a Virtual Simulation Surgical Training Environment: Effect of Experience Level and Hand Conditions(Taylor & Francis Ltd, 2018-04-10) Dalveren, Gonca Gokce Menekse; Cagiltay, Nergiz Ercil; Menekse Dalveren, Gonca GokceToday, with the advancements in the eye-tracking technology, it has become possible to follow surgeons' eye movements while performing surgical tasks. Despite the availability of studies providing a better understanding of surgeons' eye movements, research in the particular field of endoneurosurgery is very limited. Analysing surgeons' eye-movement data can provide general insights into how to improve surgical education programmes. In this study, four simulation-based task-oriented endoscopic surgery training scenarios were developed and implemented by 23 surgical residents using three different hand conditions; dominant, non-dominant, and both. The participants' recorded eye data comprised fixation number, fixation duration, saccade number, saccade duration, pursuit number, pursuit duration, and pupil size. This study has two main contributions: First, it reports on the eye-movement behaviours of surgical residents, demonstrating that novice residents tended to make more fixations and saccades than intermediate residents. They also had a higher fixation duration and followed the objects more frequently compared to the intermediates. Furthermore, hand conditions significantly affected the eye movements of the participants. Based on these results, it can be concluded that eye-movement data can be used to assess the skill levels of surgical residents and would be an important measure to better guide trainees in surgical education programmes. The second contribution of this study is the eye-movement event classifications of 10 different algorithms. Although the algorithms mostly provided similar results, there were a few conflicted values for some classifications, which offers a clue as to how researchers can utilise these algorithms with low sampling frequency eye trackers.Article Citation - WoS: 23Citation - Scopus: 28Facile synthesis of CsPbBr<sub>3</sub>/PbSe composite clusters(Taylor & Francis Ltd, 2017-12-18) Thang Phan Nguyen; Ozturk, Abdullah; Park, Jongee; Sohn, Woonbae; Tae Hyung Lee; Jang, Ho Won; Kim, Soo Young; Nguyen, Thang Phan; Lee, Tae HyungIn this work, CsPbBr3 and PbSe nanocomposites were synthesized to protect perovskite material from self-enlargement during reaction. UV absorption and photoluminescence (PL) spectra indicate that the addition of Se into CsPbBr3 quantum dots modified the electronic structure of CsPbBr3, increasing the band gap from 2.38 to 2.48 eV as the Cs:Se ratio increased to 1:3. Thus, the emission color of CsPbBr3 perovskite quantum dots was modified from green to blue by increasing the Se ratio in composites. According to X-ray diffraction patterns, the structure of CsPbBr3 quantum dots changed from cubic to orthorhombic due to the introduction of PbSe at the surface. Transmission electron microscopy and X-ray photoemission spectroscopy confirmed that the atomic distribution in CsPbBr3/PbSe composite clusters is uniform and the composite materials were well formed. The PL intensity of a CsPbBr3/PbSe sample with a 1:1 Cs: Se ratio maintained 50% of its initial intensity after keeping the sample for 81 h in air, while the PL intensity of CsPbBr3 reduced to 20% of its initial intensity. Therefore, it is considered that low amounts of Se could improve the stability of CsPbBr3 quantum dots.Article Citation - WoS: 28Citation - Scopus: 44Properties of the Laplace transform on time scales with arbitrary graininess(Taylor & Francis Ltd, 2011-11) Bohner, Martin; Guseinov, Gusein Sh.; Karpuz, Basak; Karpuzc, BaşakWe generalize several standard properties of the usual Laplace transform to the Laplace transform on arbitrary time scales. Some of these properties were justified earlier under certain restrictions on the graininess of the time scale. In this work, we have no restrictions on the graininess.Article Citation - WoS: 2Citation - Scopus: 2A Schwarz Problem for the Generalized Beltrami Equation(Taylor & Francis Ltd, 2011-06) Yuksel, UgurThis article deals with the Schwarz problem [image omitted] where is a regular domain of the complex plane. Sufficient conditions on the coefficients of the differential equation are obtained under which the operator of the corresponding problem for a system of integral equations is contractive in a certain Holder space. This leads to the existence of a unique solution of the original problem.Article New Criteria for Global Asymptotic Stability of Direct-Form Digital Filters Utilizing Single Saturation Nonlinearity(Taylor & Francis Ltd, 2011-09) Singh, VimalA new sufficient condition in the form of a state-space criterion for global asymptotic stability of direct-form digital filters utilizing single saturation nonlinearity is presented. An alternative sufficient condition in the form of a matrix frequency-domain inequality is also presented. Examples show the effectiveness of the present criteria.Article Citation - WoS: 1Citation - Scopus: 1Optoelectronic Properties of Tl3inse4 Single Crystals(Taylor & Francis Ltd, 2010-10-14) Qasrawi, A. F.; Gasanly, N. M.The crystal structure, temperature-dependent electrical conductivity, Hall coefficient, current-voltage characteristics, absorption spectra and temperature- and illumination-dependent photoconductivity of Tl3InSe4 single crystals were investigated. Tl3InSe4 crystallises in a body-centred lattice with tetragonal symmetry and belongs to the space group [image omitted]. The crystals are extrinsic p-type semiconductors and exhibit a conductivity conversion from p- to n-type at a critical temperature, Tc, of 283 K. They are observed to have Schottky diode properties in an Ag/Tl3InSe4/Ag Schottky barrier device structure. The absorption spectra displays two maxima, one related to an indirect energy band gap of 1.20 eV and another corresponding to exciton transitions. The photocurrent is observed to be strongly affected by the conductivity type of the crystal. The incident light intensity dependence of the photocurrent is found to be supralinear, linear and sublinear, indicating strong recombination at the surface, monomolecular recombination and bimolecular recombination, respectively, in the regions where the sample is p-type ([image omitted]), at [image omitted], and in the n-type region ([image omitted]). In the n-type region, the photocurrent increases with decreasing temperature down to 250 K, below which the photocurrent is temperature invariant. The change in recombination mechanism is attributed to the change in the behaviour of sensitising and recombination centres.