bluuebunny/crossref_metadata_2025_split huggingface dataset:
A‐posteriori error analysis and adaptive finite element methods for singularly perturbed convection‐diffusion equations
Authors: Reinhardt Hans‐Jürgen , Wendland W. 
Published: March 2007

AbstractFor singularly perturbed one‐dimensional convection‐diffusion equations, finite element approximations are constructed based on a so‐called approximate symmetrization of the given unsymmetric problem. Local a‐posteriori error estimates are established with respect to an appropriate energy norm where the bounds are proved to be realistic. The local bounds, called error indicators, provide a basis for a self‐adaptive mesh refinement. For a model problem numerical results are presented showing that the adaptive method detects and resolves the boundary layer.
Finite‐element method for time‐dependent euler equation
Authors: Saiac J. H. , Nedelec J.C. 
Published: March 2007

AbstractThis paper presents finite element methods to approximate inviscid incompressible flow problems.First we emphasize the conservation properties of these problems, and we show that finite element methods appear as a very natural way to find conservative schemes such as Arakawa's scheme. We give convergence theorems and an error analysis of finite element discretization schemes. We turn then to the time differencing problem. We derive stability and convergence results for a second‐order semi‐implicit scheme and for the leap‐frog scheme.
The emergence of solitons of the korteweg‐de vries equation from arbitrary initial conditions
Authors: Eckhaus W. , Schuur P. 
Published: March 2007

AbstractWe study the solution u(x, t) of the Korteweg‐de Vries equation ut − 6uux + uxxx = 0 with arbitrary initial conditions u(x, 0) = u0(x), u0(x) decaying sufficiently rapidly as |ξ|→∞. Using the method of the inverse scattering transformation we analyse the Gel'fand‐Levitan equation in all coordinate systems moving to the right and give a complete and rigorous description of the emergence of solitons.
Ein Hodge‐Satz für Mannigfaltigkeiten mit nicht‐glattem Rand
Authors: Picard R. , Leis R. 
Published: March 2007

AbstractIn this paper the question of determining the dimension of the space of harmonic Dirichlet and Neumann differential forms on a Riemannian manifold with non‐smooth boundary is answered for a wide class of boundaries. The admissible boundaries can be characterized using a generalized “global segment property”. The well‐known relation between the Betti numbers and the dimension of these spaces is established in this more general case, too. Bounded and non‐bounded manifolds are treated (“exterior and interior domains”).
Approximate inversion of the 3 D radon transform
Authors: Louis A. K. , Töring W. 
Published: March 2007

AbstractThe nuclear magnetic resonance (NMR) zeugmatography, a new technology in diagnostic medicine, leads to the problem of inverting the Radon transform in three dimensions. In contrast to even dimensions in odd dimensions the inversion formula is local. In three dimensions it consists of a backprojection operator, which brings no problems for the implementation, and taking the second derivative of the data. This is usually approximated by the central difference quotient. Here the effect of this approximate inversion operator is studied, error estimates for this ill‐posed problem are given and a stepsize is computed which minimizes the sum of discretization and data error.
The coupling of boundary integral and finite element methods for the bidimensional exterior steady stokes problem
Authors: Sequeira A. , Nedelec J.C. 
Published: March 2007

AbstractIn this paper, we represent a new numerical method for solving the steady‐state Stokes equations in an unbounded plane domain. The technique consists in coupling the boundary integral and the finite element methods. An artificial smooth boundary is introduced separating an interior inhomogeneous region from an exterior one. The solution in the exterior domain is represented by an integral equation over the artificial boundary. This integral equation is incorporated into a velocitypressure formulation for the interior region, and a finite element method is used to approximate the resulting variational problem. This is studied by means of an abstract framework, well adapted to the model problem, in which convergence results and optimal error estimates are derived. Computer results will be discussed in a forthcoming paper.
Solvability of an initial boundary value problem for the euler equations in twodimensional domain with corners
Authors: Zajaczkowski W. M. , Piskorek A. 
Published: March 2007

AbstractThe aim of this paper is to prove the existence and uniqueness of local solutions of some initial boundary value problems for the Euler equations of an incompressible fluid in a bounded domain Ω ⊂ R2 with corners. We consider two cases of a nonvanishing normal component of velocity on the boundary. In three‐dimensional case such problems have been considered in papers [12], [13], [14]. Similar problems in domains without corners have been considered in [2]–[6], [11]. In this paper the relation between the maximal corner angle of the boundary and the smoothness of the solutions is shown. The paper consists of four sections. In section 1 two initial boundary value problems for the Euler equations are formulated. In section 2 the existence and uniqueness of solutions of the Laplace equation in twodimensional domain with corners for the Dirichlet and Neumann problems is proved in the Sobolev spaces. In sections 3 and 4 we prove the existence and uniqueness of solutions of problems formulated in section 1, using the method of successive approximations.
Integral formulation for a steady‐state transport process with general boundary conditions
Authors: Busoni G. , Frosali G. , Neunzert H. 
Published: March 2007

AbstractA linear equation for a particle steady‐state transport process in a homogeneous slab of finite thickness with boundary conditions of general type is derived. This equation differs from the well‐known integral equation for no‐reentry boundary conditions because of the presence of a per‐turbance linear operator which describes the effect of the re‐emission of the particles incident at the wall. The properties of the resulting operator are investigated. The dependence of the first positive eigenvalue on physical parameters is studies in detail. The results obtained are enough to discuss the existence of a critical strictly positive solution of the physical problems which motivated this research.
Functional differential equations with certain monotonicity properties
Authors: Mierczyński J. 
Published: March 2007

AbstractThe present paper is concerned with the study of retarded differential equations in n‐space, which satisfy some monotonicity properties. Sufficient conditions are given guaranteeing that solutions are contained in the probability (n – 1)‐simplex. Existence and uniqueness of constant solutions are proved. It is also shown that every solution converges to a constant as t → ∞.
Continuous dependence on geometry for the backward heat equation
Authors: Crooke P. S. , Payne L. E. 
Published: March 2007

AbstractIn this paper we are concerned with the development of criteria for stabilizing inherently unstable initial‐boundary value problems under small errors in the geometry of the underlying domain. We consider in particular the initial‐boundary‐value problem for the backward heat equation assuming that some error has been made in characterizing the geometry of the domain under consideration. It is shown that solutions which belong to an appropriately defined constraint set depend continuously in L2 on errors in the geometry.
On the asymptotic behaviour and stability of the solution for the Broadwell model of the Boltzmann equation in three dimensions
Authors: Toscani G. , Neunzert H. 
Published: March 2007

AbstractThe initial value problem for the full Broadwell model, in gas kinetic theory, is investigated. By means of a fixed point theorem an upper estimate for the solution is derived, provided that the initial values satisfy suitable a priori conditions. Since this estimate is function of the time, the asymptotic behaviour of the global solution is determined.
On the existence of optimum large amplitude hydrofoil propulsion II
Authors: Urbach H. P. , van de Vooren A. I. 
Published: March 2007

AbstractThe possibility of optimum thrust‐production by means of a flexible profile is discussed using a linearized theory. By applying the theory of trace theorems and Rellich's lemma, it is shown that there exists an optimum path for the profile in every class which consists of paths having uniformly bounded amplitudes and slopes.
Wall effects on the slow steady motion of a particle in a viscous incompressible fluid
Authors: Fischer T. M. , Wendland W. 
Published: March 2007

AbstractIn this paper, asymptotic expansions with respect to small Reynolds numbers are proved for the slow steady motion of an arbitrary particle in a viscous, incompressible fluid past a single plane wall. The flow problem is modelled by a certain boundary value problem for the stationary, nonlinear Navier‐Stokes equations. The coefficients of these expansions are the solutions of various, linear Stokes problems which can be constructed by single layer potentials and corresponding boundary integral equations on the boundary surface of the particle. Furthermore, some asymptotic estimates at small Reynolds numbers are presented for the slow steady motion of an arbitrary particle in a viscous, incompressible fluid between two parallel, plane walls and in an infinitely long, rectilinear cylinder of arbitrary cross section.In the case of the flow problem with a single plane wall, the paper is based on a thesis, which the author has written under the guidance of Professor Dr. Wolfgang L. Wendland.
On an exterior boundary‐value problem for the time‐harmonic maxwell equations with boundary conditions for the normal components of the electric and magnetic field
Authors: Kress R. , Leis R. 
Published: March 2007

AbstractWe treat the time‐harmonic Maxwell equations with the boundary condition (ν, E) = (ν, H) = 0 in an exterior multiply connected domain. A uniqueness result by Yee for the case of a simply connected domain is extended to multiply connected domains and existence is obtained by a boundary integral equation approach.
A note on the nonlinear stability of a spatially symmetric vlasov‐possion flow
Authors: Marchioro C. , Pulvirenti M. , Neunzert H. 
Published: March 2007

AbstractWe give sufficient conditions for the nonlinear stability of a, possibly non‐smooth, spatially homogeneous Vlasov‐Poisson flow.Research partially supported by Italian CNR and Ministero della Pubblica Istruzione.
Evolution of two concentrated vortices in a two‐dimensional bounded domain
Authors: Marchioro Carlo , Pagani Enrico , Neunzert H. 
Published: March 2007

AbstractWe prove that two initially concentrated vortices with opposite vorticity of an incompressible ideal fluid moving in a two‐dimensional bounded domain, remain concentrated during the time. The motion of their centers converges to the solution of the point vortex model with the corresponding initial conditions.
Microstrip‐fed monopole dumbbell‐shaped antenna for UWB application
Authors: Tseng Ching‐Fang , Huang Cheng‐Liang 
Published: March 2007

AbstractThe monopole dumbbell‐shaped antenna fed by a 50 Ω microstrip line for ultrawideband (UWB) application is studied. By tuning the dumbbell‐shaped radiator and height of the feed gap (D), the monopole antenna has a 2:1 VSWR (return loss < 10 dB) from 2.89 to more than 15 GHz. The bandwidth covered 3.1–10.6 GHz, which has approved by the Federal Communications Commission as a commercial UWB band. Moreover, the antenna features near omnidirectional characteristics in the operation range and good radiation efficiency. The UWB, monopole characteristics of the antenna are confirmed experimentally. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1470–1473, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22404
Small area right angle bends fabricated with hybrid conventional and interference lithography
Authors: Zhou Yaling , Tan Hua , Klotzkin David J. 
Published: March 2007

AbstractA technique to fabricate high‐resolution, photonic features in selected areas aligned to large features such as waveguides, sources, or detectors without e‐beam lithography is demonstrated. This low‐cost parallel technique can be readily extended to produce resonant cavities and photonic‐crystals integrated into conventional waveguide structures. A right‐angle bend using integrated Bragg reflectors is designed and characterized. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1300–1303, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22408
Spatial diversity antenna for WLAN application
Authors: Shin Yong‐Sun , Park Seong‐Ook 
Published: March 2007

AbstractThis article presents a novel printed diversity planar monopole antenna integrated on a PCMCIA network card with minimized the mutual coupling for WLAN application at the 5 GHz bands (5150–5350 and 5725–5875 MHz). The proposed diversity antenna is printed on FR‐4 substrate and small size enough to be embedded in the laptop computer. Optimizing the separation distance and antenna parameters with use of two slots on a ground, the good isolation performance (less than −20 dB) between the two printed monopole antennas is achieved. The proposed diversity antenna has an impedance bandwidth of 2360 MHz ranging from 4520 to 6889 MHz (S11 < −10 dB). There is a good agreement between the simulated and measured results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1290–1294, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22414
Optical labeling using carrier suppressed second harmonic subcarrier label
Authors: Cho Jeong‐Sik , Won Yong‐Hyub 
Published: March 2007

AbstractA carrier‐suppressed second harmonic subcarrier‐multiplexed labeling technique for optical label switching network is demonstrated. It provides frequency doubling for optical subcarrier label so that requirement for high bandwidth optical or electrical components can be reduced. The results of two‐span transmission of 10‐Gb/s payload with 1.244‐Gb/s subcarrier label show improved performance of the labeling technique. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1468–1470, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22418
A 40‐Gb/s SCM optical communication system based on an integrated CMOS transceiver
Authors: Chen Jinghong , Saibi Fadi , Sackinger Edward , Othmer Joe , Yu Mark , Huang Titus , Liu Ting‐Ping , Azadet Kamran 
Published: March 2007

AbstractIn this letter, the feasibility of a 40‐Gb/s subcarrier multiplexed optical transmission system using low‐cost optical electronic components and CMOIS IC technology is studied. A test chip and its measurement results are reported. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1272–1274, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22433
Simultaneous negative‐ and positive‐phase‐velocity propagation in an isotropic chiral medium
Authors: Mackay Tom G. , Lakhtakia Akhlesh 
Published: March 2007

AbstractThe phase velocity of plane waves propagating in an isotropic chiral medium can be simultaneously positive for left‐circularly polarized light and negative for right‐circularly polarized light (or vice versa). The constitutive parameter regimes supporting this phenomenon are established for nondissipative and dissipative mediums. The boundary between positive‐ and negative‐phase velocity is characterized by infinite phase velocity. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1245–1246, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22434
Design and fabrication of the circularly polarized microstrip patch antenna
Authors: Hyeonjin Lee , Jung Jinwoo , Yeongseog Lim 
Published: March 2007

AbstractIn this article, circularly polarized microstrip patch antenna with a 5.8 GHz frequency for the Industrial Scientific Medical is designed and fabricated. The proposed modified cross‐slots antenna composed four separate slots by removing the intersection of the cross‐slot in conventional structure. The proposed antenna improved characteristics of the gain, radiation pattern, and impedance bandwidth than the conventional cross‐slots antenna. As a result, the proposed antenna obtains impedance bandwidth of 240 MHz (VSWR < 1.5) and maximal gain of 5 dBi. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1415–1418, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22441
A 24‐GHz power‐efficient MMIC pulse oscillator for UWB radar applications
Authors: Kim Deokhwan , Kim Dong‐Wook , Hong Songcheol 
Published: March 2007

AbstractA 24‐GHz power‐efficient pulse oscillator for ultrawideband (UWB) radar applications implemented with InGaP HBT MMIC technology is proposed. The oscillator uses a common base inductive feedback topology without output buffers. The bias current is switched on by a pulse‐control voltage. The oscillator consumes power only when the 24‐GHz pulse is generated, allowing high power efficiency to be obtained. A high output power of 8 dBm and a low phase noise of −120 dBc/Hz at 1 MHz offset frequency are obtained in continuous wave (CW) mode. While in pulse‐mode operation, the oscillator shows a 1‐ns pulse width with only 5 ps of phase jitter. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1412–1415, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22456
Simple method for a K‐band SIW filter with dual‐mode quasi‐elliptic function response
Authors: Huang Tsung‐Hui , Chang Chin‐Sheng , Chen Han‐Jan , Chen Lih‐Shan , Horng Jui‐Hong , Wang Yeong‐Her , Houng Mau‐Phon 
Published: March 2007

AbstractA simple method for a K‐band substrate integrated waveguide (SIW) filter with dual‐mode response quasi‐elliptic function response is designed, fabricated, and measured around 20 GHz. By using an orthogonal input and output (I/O) feed‐line and adjusting a perturbation, the proposed filter with two transmission‐zeros are so close to the passband that the selectivity and out‐of‐band rejection of the filter are significantly increased. The designed filter demonstrates the superior passband characteristics with a measured central frequency fo = 20 GHz, the insertion loss S21 = −2.9 dB, the return loss S11 = −23.5 dB. Experimental results of the fabricated filter measured by network analyzer are well agreed with the simulation results. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1246–1249, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22465
Equivalent circuit model of a tri‐resonance wideband dielectric resonator antenna
Authors: Ruan Yu‐Feng , Guo Yong‐Xin , Shi Xiang‐Quan 
Published: March 2007

AbstractAn equivalent circuit model of a tri‐resonance wideband dielectric resonator antenna is presented to give a physical insight into the wideband behavior of the antenna. The well‐known Levenberg–Marquardt algorithm is employed to improve the convergence characteristics of the curve fitting method used for finding the complex equivalent circuit model values having three resonators. The equivalent circuit models with various combinations of the antenna parameters such as dielectric constant, probe length, excitation position, and air‐gap are provided to verify that the proposed equivalent circuit model can give a good description of the antenna wideband behavior. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1427–1433, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22470
Wavelength‐switchable fiber laser
Authors: Medendorp Zachari , Valiunas Jonas , Das Gautam 
Published: March 2007

AbstractA simple and novel technique to produce a switchable erbium‐doped fiber laser is proposed and demonstrated. The wavelength switching is achieved by changing the input pump power. The lasing lines are stable for more than an hour at room temperatures. The effects of separation between the lasing lines and the length of the erbium‐doped fiber on switching are explored. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1231–1233, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22477
Liver receptor homologue‐1 (LRH‐1) activates the promoter of brain aromatase (cyp19a2) in a teleost fish, the medaka, Oryzias latipes
Authors: Ohmuro‐Matsuyama Yuki , Okubo Kataaki , Matsuda Masaru , Ijiri Shigeho , Wang Deshou , Guan Guijun , Suzuki Taiga , Matsuyama Makoto , Morohashi Ken‐ichiro , Nagahama Yoshitaka 
Published: March 2007

AbstractThe medaka, Oryzias latipes, like other fish, have two distinct aromatase genes, the ovarian (cyp19a1) and brain (cyp19a2) forms. We previously reported that Ad4BP/SF‐1, a member of the NR5A subfamily, plays an important role in the regulation of cyp19a1 expression in medaka ovarian follicles during vitellogenesis. In the present study, we investigated whether liver receptor homologue‐1 (LRH‐1), another NR5A subfamily member, is involved in the regulation of cyp19a2 expression in the medaka brain. In situ hybridization analysis revealed that LRH‐1 was expressed in the hypothalamus, where it colocalized with aromatase (cyp19a2). We then showed by transient transfection assays that LRH‐1 was able to increase expression of a cyp19a2 reporter gene in various mammalian cell lines, and that mutation of a putative LRH‐1 binding site within the cyp19a2 promoter abolished this effect. Taken together, these findings suggest that LRH‐1 plays a role in regulating cyp19a2 expression in the medaka brain. This is the first to demonstrate in vitro the activation of brain aromatase by LRH‐1 in the vertebrate brain. Mol. Reprod. Dev. 74: 1065–1071, 2007. © 2007 Wiley‐Liss, Inc.
The split delivery vehicle routing problem: Applications, algorithms, test problems, and computational results
Authors: Chen Si , Golden Bruce , Wasil Edward 
Published: March 2007

AbstractIn the split delivery vehicle routing problem (SDVRP), a customer's demand can be split among several vehicles. In this article, we review applications of the SDVRP including the routing of helicopters in the North Sea and solution methods such as integer programming and tabu search. We develop a new heuristic that combines a mixed integer program and a record‐to‐record travel algorithm. Our heuristic produces high‐quality solutions to six benchmark problems that have 50–199 customers and generally performs much better than tabu search. On five other problems for which lower bounds exist, our heuristic obtains solutions within 5.85%, on average. Finally, we generate 21 new test problems that have 8–288 customers. A near‐optimal solution can be visually estimated for each problem. We apply our heuristic to these new problems and report our computational results. © 2007 Wiley Periodicals, Inc. NETWORKS, Vol. 49(4), 318–329 2007
Maximum‐norm superapproximation of the gradient for the trilinear block finite element
Authors: Liu Jinghong , Zhu Qiding 
Published: March 2007

AbstractFor a model elliptic boundary value problem in three dimensions, we give the weak estimate of the first type for trilinear block elements and the estimate for W1,1‐seminorm of the discrete derivative Green's function over rectangular partitions of the domain, from which we obtain maximum‐norm superapproximation of the gradient for the trilinear block finite element approximation. Furthermore, utilizing this superapproximation, we can also obtain maximum‐norm superconvergence of the gradient. © 2007 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2007