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Article Citation - WoS: 1Electrochemistry of Acetate-, Carbonate-, Sulfate-, and Dihydrogenphosphate-Bridged Dirhodium(ii) Complexes(verlag Z Naturforsch, 2003) Yaman, SO; Önal, AM; Isci, HComplexes, [Rh-2(B-B)(4)L-2](n) (B-B = CH3CO2-, L = CH3CN, H2O, Cl-, Br-, SCN-; B-B CO32-, SO42-, H2PO4-, L = H2O, Cl-, Br-, SCN-) were prepared and their cyclic voltammograms (CV) and electronic absorption spectra were measured in solution. The CV of the complexes exhibits a reversible one-electron transfer from a metal-based orbital. Constant potential electrolysis at the oxidation peak potential of [Rh-2(O2CCH3)(4)(NCCH3)(2)] in acetonitrile yielded [Rh-2(O2CCH3)(4)(NCCH3)(2)](+), a mixed valent Rh(II)-Rh(III) cation complex. The formation of the mixed valent complex was monitored by measuring electronic absorption spectra of the solution in situ during the oxidative electrolysis. The reductive electrolysis of the mixed valent complex solution, in the same electrolysis cell, yielded the original electronic absorption spectrum of the starting complex. The changes in the oxidation and reduction potentials of the complexes with different axial ligands, L = H2O, Cl-, Br-, SCN-, are correlated to the relative energy changes of HOMO and LUMO of the complexes, which indicates the metal-axial ligand sigma- and pi-bonding interactions. Spectroscopic and CV data indicate that the degree of a-interaction is Cl- > Br- > SCN-, and that of pi-interaction is Br- > SCN- > Cl-.Article Citation - WoS: 7Citation - Scopus: 10A FUZZY CONCEPTUAL MODEL FOR MULTIMEDIA DATA WITH A TEXT-BASED AUTOMATIC ANNOTATION SCHEME(World Scientific Publ Co Pte Ltd, 2009) Kucuk, Dilek; Burcuozgur, N.; Yazici, Adnan; Koyuncu, MuratThe size of multimedia data is increasing fast due to the abundance of multimedia applications. Modeling the semantics of the data effectively is crucial for proper management of it. In this paper, we present a fuzzy conceptual data model for multimedia data which is also generic in the sense that it can be adapted to all multimedia domains. The model takes an object-oriented approach and it handles fuzziness at different representation levels where fuzziness is inherent in multimedia applications and should be properly modeled. The proposed model also has the nice feature of representing the structural hierarchy of multimedia data as well as the spatial and temporal relations of the data. The model is applied to the news video domain and implemented as a fuzzy multimedia database system where it turns out to be effective in representing the domain and thereby provides an evidence for the general applicability of the model. The model is accompanied by an automatic multimedia annotation scheme which makes use of information extraction techniques on the corresponding multimedia texts.Article Citation - Scopus: 8Computation of a Tunable Slot-Loaded Equilateral Triangular Microstrip Antenna(2009) Aydın,E.In this paper, a simple closed form expression is developed to accurately estimate the lower and upper operating frequencies of a single feed slot loaded triangular patch (SLTP) with variations of the bent slot lengths. It is obtained by using cavity model analysis and useful to antenna engineers for accurately predicting both operating resonant frequencies of the SLTP. The theory is compared with the experimental results available in the literature, and excellent agreement is observed. The proposed computation is also extended to the analysis of tunability of the SLTP as a function of the air-gap height. © Journal of electromagnetic waves and applications. All Rights reserved.Article On the Definition of Sequential Consistency(Elsevier Science Bv, 2005) Sezgin, A; Gopalakrishnan, GThe definition of sequential consistency is compared with an intuitive notion of correctness. That the definition is not strong enough is illustrated through a hypothetical memory system which is clearly incorrect, yet sequentially consistent. It is claimed that the reason for this is the absence of a relation between what actually happens (temporal order) and what seems to happen (logical order). A stronger version of sequential consistency is proposed. (c) 2005 Elsevier B.V. All rights reserved.Article Citation - WoS: 12Citation - Scopus: 15Discrete Parameter-Nonlinear Constrained Optimisation of a Gear Train Using Genetic Algorithms(inderscience Enterprises Ltd, 2005) Dolen, M.; Kaplan, H.; Seireg, A.This paper investigates the optimal design of a four-stage gear train using genetic algorithms. Five different genetic encoding schemes, which incorporate various heuristic search techniques, are proposed to deal with the most critical constraints of the problem. The fitness criterion used by all genetic algorithms includes a merit function for minimising the size of the gearbox. The results show improvement in the design merit over previous approaches without reliance on the designer's interaction to avoid geometric constraint violations and facilitate the convergence.Article Citation - WoS: 23Citation - Scopus: 25Comparison of Cellular Proliferation on Dense and Porous Pcl Scaffolds(Ios Press, 2008) Sasmazel, Hilal Tuerkoglu; Gumusderelioglu, Menemse; Gurpinar, Aylin; Onur, Mehmet AliIn this contribution, PCL (poly-e caprolactone) scaffolds were prepared by solvent-casting/particle-leaching technique in the presence of two pore formers, PEG(4000) or sucrose molecules in different quantities (0, 10, 20, 30, 40, 50, 55 w/w% PEG(4000)/PCL; 10, 20 w/w% Sucrose/ PCL). The surface and bulk properties of the resulting scaffolds were studied by SEM, DSC and FTIR. SEM photographs showed that, macroporosity was obtained in the PCL structures prepared with sucrose crystals while microporous structure was obtained in the presence of PEG(4000) molecules. Average pore diameters calculated from SEM photographs were 40.1 and 191.2 mu m for 40% PEG(4000)/PCL and 10% Sucrose/PCL scaffolds, respectively. The DSC and FTIR results confirmed that there is no any interaction between pore formers and PCL during structural formation, and both pore formers, PEG(4000) and sucrose, remained independently in the scaffolds. L929 mouse fibroblast cells were seeded onto PCL structures and maintained during 7 days to evaluate cell proliferation. Cell culture results showed that, 10% Sucrose/ PCL scaffold was the most promising substrate for L929 cell growth due to 3-D architecture and macroporous structure of the scaffold.Article Citation - WoS: 7Computation of a Tunable Slot-Loaded Equilateral Triangular Microstrip Antenna(Vsp Bv, 2009) Aydin, E.In this paper, a simple closed form expression is developed to accurately estimate the lower and upper operating frequencies of a single feed slot loaded triangular patch (SLTP) with variations of the bent slot lengths. It is obtained by using cavity model analysis and useful to antenna engineers for accurately predicting both operating resonant frequencies of the SLTP. The theory is compared with the experimental results available in the literature, and excellent agreement is observed. The proposed computation is also extended to the analysis of tunability of the SLTP as a function of the air-gap height.Article Citation - WoS: 1Citation - Scopus: 3Evaluation of New Codes for Spectral-Amplitude Optical Code-Division Multiple-Access Communication Systems(Spie-int Society Optical Engineering, 2004) Murugesan, K; Ravichandran, VCNew classes of codes, namely extended modified prime sequence codes (EMPSC) and difference codes, both having an ideal in-phase cross-correlation (IPCC) value of one, are suggested for spectral-amplitude-coding optical code-division multiple-access communication systems. The general structure of the system is discussed with simpler encoder and decoder architectures based on fiber Bragg gratings. Since the influence of multiuser interference can be completely removed due to ideal IPCC, the performance analyses of the proposed codes have been carried out by incorporating the effects of phase-induced intensity noise (PIIN), shot noise, and thermal noise at the receiver, employing Gaussian approximation. Assuming typical system parameters, evaluation results show that with an increase in code weight, the maximum number of accommodative users in the system can be increased as well as significant improvements in bit error probability for a given number of active users. For the same code weight, the difference codes can support a greater number of simultaneous users than the other. It is found that the effects of PIIN dominate compared to shot noise and thermal noise at large powers, whereas the effects of PIIN and shot noise are highly reduced at low powers, so that thermal noise becomes a more influential limitation factor. In comparison with earlier codes, the error performance of EMPSC is similar to that of modified quadratic congruence codes, while difference codes resemble those codes developed based on Steiner systems. (C) 2004 Society of Photo-Optical Instrumentation Engineers.Letter Citation - WoS: 22Citation - Scopus: 24A Note on Determination of Oscillation Startup Condition(Springer, 2006) Singh, VimalThere prevails a widespread notion that, given a closed-loop system, oscillation will commence and build up therein if the magnitude of loop gain is greater than unity at the frequency at which the angle of loop gain is zero degree. Three novel examples in which this notion fails are presented.Article Citation - WoS: 4Citation - Scopus: 5Roof Shape Modelling for Multiple Diffraction Loss in Cellular Mobile Communication Systems(Taylor & Francis Ltd, 2002) Kara, A; Yazgan, EThe effects of roof shapes on multiple diffraction loss in cellular mobile communication systems are investigated. Building roofs are modelled as finitely conducting wedges with different, included angles (peaked roofs). Multiple diffraction loss, a measure of diffraction loss due to multiple building geometry, is computed by using the method of UTD (uniform theory of diffraction) for 90degrees and 120degrees wedges over the communication paths oblique to building blocks. The results, compared with the absorbing edge model, 0degrees wedge, show that multiple diffraction loss decreases with increasing wedge angle.
