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Studies On Extremal Segments In Random Sequences, Deniz Ertaş, Yacov Kantor Jan 1999

Studies On Extremal Segments In Random Sequences, Deniz Ertaş, Yacov Kantor

Turkish Journal of Physics

We review our main findings on the size distribution of the largest neutral segments in a sequence of N randomly charged monomers. Upon mapping to one--dimensional random walks (RWs), this corresponds to finding the probability distribution for the size L of the largest segment that returns to its starting position in an N--step RW. Using analytical, exact enumeration, and Monte Carlo methods, we reveal the complex structure of the probability distribution in the large N limit. In particular, the size of the longest neutral segment has a distribution with a square-root singularity at \ell\equiv L/N = 1, an essential singularity …


Orbital Period Modulation In Chromospherically Active Close Binaries, Cafer İbanoğlu Jan 1999

Orbital Period Modulation In Chromospherically Active Close Binaries, Cafer İbanoğlu

Turkish Journal of Physics

The orbital period changes in some chromospherically active close binaries have been interpreted as a consequence of magnetic activity. At least in two active close binaries a possible relationship between the orbital period modulation and activity cycle was suggested. The existence of a third companion in these binaries has also been proposed. The light-time effect which arises from orbiting around a third-body has been subtracted from all the O-C values and a cyclic change of the orbital period has been obtained. These cyclic changes seem to be connected with the total brightness variations at least in two samples, namely, V471 …


Cover And Contents Jan 1999

Cover And Contents

Turkish Journal of Veterinary & Animal Sciences

No abstract provided.


Focal Dermal Hypoplasia (Goltz Syndrome) In Amale Infant, Hülya Bi̇lgen, Eren Özek, Cengi̇z Canpolat, Oya Gürbüz, Müyesser Tuncer Jan 1999

Focal Dermal Hypoplasia (Goltz Syndrome) In Amale Infant, Hülya Bi̇lgen, Eren Özek, Cengi̇z Canpolat, Oya Gürbüz, Müyesser Tuncer

Turkish Journal of Medical Sciences

No abstract provided.


Natural Terrestrial Electromagnetic Fields Of Extremely Low Frequencies And Detection Of Periodic Gravitational Radiation, L. V. Grunskaya, D. V. Vinogradov Jan 1999

Natural Terrestrial Electromagnetic Fields Of Extremely Low Frequencies And Detection Of Periodic Gravitational Radiation, L. V. Grunskaya, D. V. Vinogradov

Turkish Journal of Physics

The present research is connected with nontraditional ways of detecting periodic gravitational radiation. Some records of extremely low frequency variations of electromagnetic fields of Earth with extracting periodicities are realized corresponding to the source of gravitational radiation of geophysical and astrophysical origin.


On The Global Stabilization Of Nonlinear Systems Via Switching Manifolds, Stephen P. Banks, Meti̇n U. Salamci, M. Kemal Özgören Jan 1999

On The Global Stabilization Of Nonlinear Systems Via Switching Manifolds, Stephen P. Banks, Meti̇n U. Salamci, M. Kemal Özgören

Turkish Journal of Electrical Engineering and Computer Sciences

The global stabilization of nonlinear systems is investigated by using switching surfaces. The nonlinear system is forced to a lower order switching manifold, which is designed to be stable by construction. Thus, the stability of the reduced-order system is guaranteed and parameter selection for the switching surface is avoided. The method is extended to a class of uncertain nonlinear systems and exemplified with some fictitious dynamic models.


A Simple Formula Obtained Using Tabu Search Algorithm For The Radiation Efficiency Of A Resonant Rectangular Microstrip Antenna, Dervi̇ş Karaboğa, Keri̇m Güney Jan 1999

A Simple Formula Obtained Using Tabu Search Algorithm For The Radiation Efficiency Of A Resonant Rectangular Microstrip Antenna, Dervi̇ş Karaboğa, Keri̇m Güney

Turkish Journal of Electrical Engineering and Computer Sciences

A new simple formula for the radiation efficiency of a resonant rectangular microstrip patch antenna is presented. The formula is obtained by using a tabu search algorithm, which is a quite new optimization technique based on the principles of intelligent problem solving. The formula is valid for substrates with relative permittivities between 1 and 12.8 and for the complete range of thicknesses normally used. The results obtained by using this new simple formula are in conformity with those reported elsewhere. The formula can also be used in the calculation of the radiation efficiency of dipoles.


Effects Of Parasitic Elements On Oscillation Frequency Of Ota-C Sinusoidal Oscillators, Ari̇f Nacaroğlu, Ergun Erçelebi̇ Jan 1999

Effects Of Parasitic Elements On Oscillation Frequency Of Ota-C Sinusoidal Oscillators, Ari̇f Nacaroğlu, Ergun Erçelebi̇

Turkish Journal of Electrical Engineering and Computer Sciences

An oscillator circuit which incorporates Operational Transconductance Amplifiers is presented. The circuit is designed using three OTAs and two grounded capacitors. The frequency of oscillation is tunable over a wide frequency range. The effects of the parasitic elements on the oscillation frequency and the oscillation condition are studied. The theoretical results are compared with the experimental results for a practical oscillator circuit.


Cover And Contents Jan 1999

Cover And Contents

Turkish Journal of Electrical Engineering and Computer Sciences

No abstract provided.


Cover And Contents Jan 1999

Cover And Contents

Turkish Journal of Zoology

No abstract provided.


Cover And Contents Jan 1999

Cover And Contents

Turkish Journal of Zoology

No abstract provided.


A Fake Cusp And A Fishtail, Selman Akbulut Jan 1999

A Fake Cusp And A Fishtail, Selman Akbulut

Turkish Journal of Mathematics

No abstract provided.


A Program To Search For Homotopy 3-Spheres, Michael Greene, Colin Rouke Jan 1999

A Program To Search For Homotopy 3-Spheres, Michael Greene, Colin Rouke

Turkish Journal of Mathematics

No abstract provided.


A New Approach To Immersion Theory, Colin Rourke, Brian Sanderson Jan 1999

A New Approach To Immersion Theory, Colin Rourke, Brian Sanderson

Turkish Journal of Mathematics

No abstract provided.


Seiberg-Witten Invariants Of Mapping Tori,Symplectic Fixed Points, And Lefschetz Numbers, Dietmar A. Salamon Jan 1999

Seiberg-Witten Invariants Of Mapping Tori,Symplectic Fixed Points, And Lefschetz Numbers, Dietmar A. Salamon

Turkish Journal of Mathematics

No abstract provided.


Simply Connected Symplectic 4-Manifolds Withpositive Signature, Andras I. Stipsicz Jan 1999

Simply Connected Symplectic 4-Manifolds Withpositive Signature, Andras I. Stipsicz

Turkish Journal of Mathematics

No abstract provided.


Virtual Neighborhoods And Pseudo-Holomorphic Curves, Yongbin Ruan Jan 1999

Virtual Neighborhoods And Pseudo-Holomorphic Curves, Yongbin Ruan

Turkish Journal of Mathematics

No abstract provided.


Cover And Contents Jan 1999

Cover And Contents

Turkish Journal of Mathematics

No abstract provided.


Countable Dense Homogeneous Bıtopologıcal Spaces, Abdalla Tallafha, Adnan Al-Bsoul, Ali̇ Ahmad Fora Jan 1999

Countable Dense Homogeneous Bıtopologıcal Spaces, Abdalla Tallafha, Adnan Al-Bsoul, Ali̇ Ahmad Fora

Turkish Journal of Mathematics

In this paper we shall introduce the concept of being countable dense homogeneous bitopological spaces and define several kinds of this concept. We shall give some results concerning these bitopological spaces and their relations. Also, we shall prove that all of these bitopological spaces satisfying the axioms p-T_0 and p-T_1.


Left Adjoint Of Pullback Cat^1 -Groups, Murat Alp Jan 1999

Left Adjoint Of Pullback Cat^1 -Groups, Murat Alp

Turkish Journal of Mathematics

In [1] we define the pullback Cat^1-groups and showed that the category of pullback Cat^1-groups is equivalent to the category of pullback crossed modules. In this paper we proved that the pullback Cat^1-group has a left adjoint which is the induced Cat^1-group. We also give the left adjoint construction.


Normal Subgroups And Elements Of H^{'}(\Lambda_Q), İsmai̇l Naci̇ Cangül Jan 1999

Normal Subgroups And Elements Of H^{'}(\Lambda_Q), İsmai̇l Naci̇ Cangül

Turkish Journal of Mathematics

In this study, we consider the normal subgroups of H^{'}(\lambda_q), where H(\lambda_q) denotes the Hecke groups. After recalling some results from [2], particularly on the group structure and on the relations with the power subgroups of H(\lambda_q), the even subgroup H_e(\lambda_q) of H(\lambda_q) is discussed. It is shown that H^{'}(\lambda_q) is a normal subgroup of H_e(\lambda_q) with index q. For this reason each subgroup of H^{'}(\lambda_q) consists of only even elements. H^{''}(\lambda_q) is also considered and it is concluded that it is the normal subgroup of H^{'}(\lambda_q) generated by all commutators of the elements of H^{'}(\lambda_q). Using the Kurosh subgroup …


On The Boundedness Of Integral Operators, İsmai̇l Eki̇nci̇oğlu, Isroil A. Ikromov Jan 1999

On The Boundedness Of Integral Operators, İsmai̇l Eki̇nci̇oğlu, Isroil A. Ikromov

Turkish Journal of Mathematics

In this paper, we consider integal operators defined by kernel functions. It is well known the boundedness of such kind of operators as Shur Lemma type statements. But, the norm of operators was estimated by two integrals of kernel function. We obtain estimation of operators norm by one integral of kernel function.


Some Asymptotic Estimates For The Instability Intervals Of Hill's Equation, Haskiz Coşkun Jan 1999

Some Asymptotic Estimates For The Instability Intervals Of Hill's Equation, Haskiz Coşkun

Turkish Journal of Mathematics

In this study, some asymptotic estimates for the length of the instability intervals of Hill's equation, y''(t)+(\lambda -q(t))y(t)=0, are derived by means of an auxiliary eigenvalue problem under various assumptions on the Fourier coefficients of the potential q.


Geodesics In A Tensor Bundle, Abdullah Kopuzlu, Ari̇f A. Salimov Jan 1999

Geodesics In A Tensor Bundle, Abdullah Kopuzlu, Ari̇f A. Salimov

Turkish Journal of Mathematics

The main purpose of the present paper is to study geodesics in a tensor bundle T^{p}_q(M_n) with respect to the horizontal lift ^H\nabla of an affine connection \nabla .


A Stone's Representation Theorem And Some Applications, Eissa D. Habil Jan 1999

A Stone's Representation Theorem And Some Applications, Eissa D. Habil

Turkish Journal of Mathematics

In this paper, we prove the following form of Stone's representation theorem: Let \sum be a \sigma-algebra of subsets of a set X. Then there exists a totally disconnected compact Hausdorff space {\cal K} for which (\sum, \cup, \cap) and ({\cal C}({\cal K}), \cup ,\cap), where {\cal C}({\cal K}) denotes the set of all clopen subsets of {\cal K}, are isomorphic as Boolean algebras. Furthermore, by defining appropriate joins and meets of countable families in {\cal C}({\cal K}), we show that such an isomorphism preserves \sigma-completeness. Then, as a consequence of this result, we obtain the result that if ba(X,\sum) …


Univalent Harmonic Mappings Onto Half Planes, Meti̇n Öztürk Jan 1999

Univalent Harmonic Mappings Onto Half Planes, Meti̇n Öztürk

Turkish Journal of Mathematics

We consider the class S_H(D,\Omega ) of complex functions f which are univalent, harmonic, sense preserving on a simple connected domain D\neq {\Bbb C} \ containing the origin, satisfy f(0)=a_0, f_{\bar z}(0)=0a,\ a\in {\Bbb R}\}. In particularly, we describe the closure \overline{S_H(D,\Omega )} of S_H(D,\Omega ) and characterize its extreme points, as well as sharp estimates for coefficients and distortion theorems.


Criteria Of Le Page Type In Involutive Banach Algebras, Abdellah El Kinani, Mohamed Oudadess Jan 1999

Criteria Of Le Page Type In Involutive Banach Algebras, Abdellah El Kinani, Mohamed Oudadess

Turkish Journal of Mathematics

The Le Page inequality in Banach algebras is \parallel xy \parallel\leq\alpha\parallel yx\parallel. We consider inequalities where a linear involution appears and has consequences on the involution itself and commutativity results.^1


Segal Algebra As An Ideal In Its Second Dual Space, Heybet S. Mustafayev Jan 1999

Segal Algebra As An Ideal In Its Second Dual Space, Heybet S. Mustafayev

Turkish Journal of Mathematics

For a locally compact group G, let S(G) be a symmetric Segal algebra. We prove that S(G) is an ideal in its second dual space if and only if G is compact, where the second dual is equipped with an Arens multiplication.


Some Results On Space-Like Line Congruences And Their Space-Like Parameter Ruled Surface, E. Özyilmaz Jan 1999

Some Results On Space-Like Line Congruences And Their Space-Like Parameter Ruled Surface, E. Özyilmaz

Turkish Journal of Mathematics

Using dual vectors, space-like ruled surfaces was introduced in [2]. In this paper, we define space-like line congruence and their space-like parameter ruled surfaces {\mathbf R_{11}(t)} and {\mathbf R_{21}(t)} of R_1^3. Then, by choosing space-like parameter ruled surfaces as space-like principle ruled surfaces, we obtain some relations among the magnitudes of space-like ruled surfaces {\mathbf R_1(t)}, {\mathbf R_{11}(t)}.


Cycloidal Normal Subgroups Of Hecke Groups Of Finite Index, İsmai̇l Naci̇ Cangül, Osman Bi̇zi̇m Jan 1999

Cycloidal Normal Subgroups Of Hecke Groups Of Finite Index, İsmai̇l Naci̇ Cangül, Osman Bi̇zi̇m

Turkish Journal of Mathematics

Cycloidal normal subgroups, that is, subgroups with only one cusp, of finite index of Hecke groups, which have been introduced by E. Hecke, and can be thought of as some kind of generalisation of the well-known modular group, are studied. It is shown that they correspond to cyclic quotients of Hecke groups and therefore have non-compact associated Riemann surfaces with a cusp. Finally, their total number have been formulated.