A cuckoo search optimization scheme for non-convex economic load dispatch

This paper presents a Cuckoo Search (CS) based algorithm to solve constrained economic load dispatch (ELD) problems. The proposed methodology easily deals with non-smoothness of cost function arising due to the use of valve point effects. The performance of the algorithm has been tested on systems possessing 13 and 40 generating units involving varying degrees of complexity. The findings affirm that the method outperforms the existing techniques, and can be a promising alternative approach for solving the ELD problems in practical power system

Bound - states for truncated Coulomb potentials

The pseudoperturbative shifted - $l$ expansion technique PSLET is generalized for states with arbitrary number of nodal zeros. Bound- states energy eigenvalues for two truncated coulombic potentials are calculated using PSLET. In contrast with shifted large-N expansion technique, PSLET results compare excellently with those from direct numerical integration.Comment: TEX file, 22 pages. To appear in J. Phys. A: Math. & Ge

Unidirectional Invisibility and PT-Symmetry with Graphene

We investigate the reflectionlessness and invisibility properties in the transverse electric (TE) mode solution of a linear homogeneous optical system which comprises the $\mathcal{PT}$-symmetric structures covered by graphene sheets. We derive analytic expressions, indicate roles of each parameter governing optical system with graphene and justify that optimal conditions of these parameters give rise to broadband and wide angle invisibility. Presence of graphene turns out to shift the invisible wavelength range and to reduce the required gain amount considerably, based on its chemical potential and temperature. We substantiate that our results yield broadband reflectionless and invisible configurations for realistic materials of small refractive indices, usually around $\eta = 1$, and of small thickness sizes with graphene sheets of rather small temperatures and chemical potentials. Finally, we demonstrate that pure $\mathcal{PT}$-symmetric graphene yields invisibility at small temperatures and chemical potentials.Comment: 20 pages, 1 table 17 figure

Can Van Hove singularities be observed in relativistic heavy-ion collisions ?

Based on general arguments the in-medium quark propagator in a quark-gluon plasma leads to a quark dispersion relation consisting of two branches, of which one exhibits a minimum at some finite momentum. This results in a vanishing group velocity for collective quark modes. Important quantities such as the production rate of low mass lepton pairs and mesonic correlators depend inversely on this group velocity. Therefore these quantities, which follow from self energy diagrams containing a quark loop, are strongly affected by Van Hove singularities (peaks and gaps). If these sharp structures could be observed in relativistic heavy-ion collisions it would reveal the physical picture of the QGP as a gas of quasiparticles.Comment: 12 pages including nine figures and style files, invited talk given at the ICPAQGP-2001, November 26-30, 2001, Jaipur, Indi

Development of an Arabic text-to-speech system

Research on Text-to-speech technology has received the interest of professional researchers in many languages which is a consequence of wide range of applications where Text-To-Speech is implemented. However, Arabic language, spoken by millions of people as an official language in 24 different countries, gained less attention compared with other languages despite the fact that it has a religious value for more than 1.6 billion Muslim worldwide. These facts exhibit the need for a high quality, smallsize, and completely free Arabic TTS with the ability of future improvements. The vowelized written text of Arabic language carries the pronunciation rules with limited exceptions, so rulebased system with an exception dictionary for words that fail with those letter-to-phoneme rules may be a much more reasonable approach. This paper is a development of a rulebased text-to-speech Hybrid synthesis system which is a combination formant and concatenation techniques with acceptable naturalness. The simulation results of the system shows good quality in handling word, phrase, and sentence level compared to other available Arabic TTS systems. The accuracy of the overall system is 96%. Further improvements need to be done for stressed syllable position and intonation

Between a rock and a hard place: corporate elites in the context of religion and secularism in Turkey

Drawing on discourse analyses of 36 in-depth interviews with elite business people from Turkey, the study identifies the networking patterns of new and established business elites in the context of economic liberalization and socioreligious transformation of the country. Through a comparative analysis of the so-called secular and religious elite networks, we demonstrate the role of institutional actors such as the government, and identity networks, based on religion and place of birth in shaping the form and content of social networks among business elites in Turkey. In order to achieve this, we operationalize Bourdieu's notion of theory of practice and Granovetter's theory of social networks, illustrating the utility of combining these approaches in explicating the form and content of social networks in their situated contexts, in which power and divergent interests are negotiated.Galatasaray University Research Fund [grant number 12.102.005]

Dirac eigenvalues for a softcore Coulomb potential in d dimensions

A single fermion is bound by a softcore central Coulomb potential V(r) = -v/(r^q + b^q)^(1/q), v>0, b>0, q \ge 1, in d>1 spatial dimensions. Envelope theory is used to construct analytic lower bounds for the discrete Dirac energy spectrum. The results are compared to accurate eigenvalues obtained numerically.Comment: 8 pages 1 figur

Algorithm for Fault Location and Classification on Parallel Transmission Line using Wavelet based on Clarke’s Transformation

This paper proposed a new algorithm for fault location and classification using wavelet based on Clarke’s transformation to obtain the fault current. This novel method of fault current approach is studied by comparing the use of the glide path of the fault voltage. The current alpha and beta (Current Mode) were used to transform the signal using discrete wavelet transform (DWT). The fault location was determined by using the Clarke’s transformation, and then turned into a wavelet, which was very precise and thorough. The most accurate was the mother wavelet Db4 which had the fastest time and smallest error detection when compared with the other wavelet mothers. In this study, the Clarke’s transformation is also compared with the Karenbauer’s, which has produced results with similar error percentage. The simulation results using PSCAD / EMTDC software showed that the proposed algorithm could distinguish internal and external faults to get the current signal in the transformation of a signal fault

New Singular and Nonsingular Colliding Wave Solutions in Einstein - Maxwell - Scalar Theory

A technique is given to generate coupled scalar field solutions in colliding Einstein - Maxwell (EM) waves. By employing the Bell - Szekeres solution as seed and depending on the chosen scalar field it is possible to construct nonsingular solutions. If the original EM solution is already singular addition of scalar fields does not make the physics any better. In particular, scalar field solution that is transformable to spherical symmetry is plagued with singularities.Comment: 15 pages, To be published in GR

Broadband and Wide-Angle Invisibility with PT-Symmetric 2D-Weyl Semimetal

Inspired by the magnificent features of two-dimensional (2D) materials which aroused much of the interest in recent materials science research, we study PT-symmetric 2D Weyl semimetal (WSM) to reveal the broadband and wide-angle invisible configurations in a PT-symmetric optical slab system. Desired unidirectional reflectionlessness and invisibility phenomena is obtained by the optimal control of system parameters. We unravel the mystery of broadband and wide-angle invisibility in regular slab materials with finite refractive indices by means of the plenary expressions. We show that materials whose refractive indices relatively small (usually around $\eta =1$) give rise to quite a lot broadband and wide-angle (almost all incidence angles) invisible configurations. This is not observed with any 2D material other than 2D WSMs. Our findings suggest a concrete expedience to experimental realizations in this direction.Comment: 8 pages, 11 figure