24,604 research outputs found
Time-Efficient resource allocation algorithm over HSDPA in femtocell networks
This paper presents a time-efficient optimal resource allocation algorithm aiming to maximize the system throughput of the single-user High Speed Downlink Packet Access (HSDPA) deployed in femtocell base station. The system throughput maximization with constrained total power is rst formulated as a constrained integer programming problem. We rst prove that a two-group bit and energy allocation provides the global optimum solution in the system without multipath. We then focus on the use of the two-group allocation method over frequency selective channels. A pre-processing method was used to systematically cluster and remove channels to stop using energies over severely degraded channels with the two-group allocation approach. This improves the system throughput whilst greatly reducing the computation complexity. The proposed twogroup approach with channel removal is suitable for femtocell base station with limited signal processing capability.Accepted versio
Exact solution of type quantum Calogero model through a mapping to free harmonic oscillators
We solve the eigenvalue problem of the type of Calogero model by
mapping it to a set of decoupled quantum harmonic oscillators through a
similarity transformation. In particular, we construct the eigenfunctions of
this Calogero model from those of bosonic harmonic oscillators having either
all even parity or all odd parity. It turns out that the eigenfunctions of this
model are orthogonal with respect to a nontrivial inner product, which can be
derived from the quasi-Hermiticity property of the corresponding conserved
quantities.Comment: 16 page
Wavelet analysis of beam-soil structure response for fast moving train
This paper presents a wavelet based approach for the vibratory analysis of beam-soil structure related to a point load moving along a beam resting on the surface. The model is represented by the Euler-Bernoulli equation for the beam, elastodynamic equation of motion for the soil and appropriate boundary conditions. Two cases are analysed: the model with a half space under the beam and the model where the supporting medium has a finite thickness. Analytical solutions for the displacements are obtained and discussed in relation to the used boundary conditions and the type of considered loads: harmonic and constant. The analysis in time-frequency and velocity-frequency domains is carried out for realistic systems of parameters describing physical properties of the model. The approximate displacement values are determined by applying a wavelet method for a derivation of the inverse Fourier transform. A special form of the coiflet filter used in numerical calculations allows to carry out analysis without loss of accuracy related to singularities appearing in wavelet approximation formulas, when dealing with standard filters and complex dynamic systems. © 2009 IOP Publishing Ltd
Learning from openness : the dynamics of breadth in external innovation linkages
We explore how openness in terms of external linkages generates learning effects, which enable firms to generate more innovation outputs from any given breadth of external linkages. Openness to external knowledge sources, whether through search activity or linkages to external partners in new product development, involves a process of interaction and information processing. Such activities are likely to be subject to a learning process, as firms learn which knowledge sources and collaborative linkages are most useful to their particular needs, and which partnerships are most effective in delivering innovation performance. Using panel data from Irish manufacturing plants, we find evidence of such learning effects: establishments with substantial experience of external collaborations in previous periods derive more innovation output from openness in the current period
Congenital Nasolacrimal Duct Obstruction at Prince Rashed Hospital, Irbid,
Objectives: To estimate the frequency of congenital nasolacrimal duct
obstruction (CNLDO) and to assess the results of its management.
Material and Methods: A prospective study of 80 consecutive patients with
congenital nasolacrimal duct obstruction, conducted from January 2005 to December 2005 at Prince Rashed Hospital. Only patients below the age of twelve months were included in the study. Diagnosis was made by history of epiphora beginning early in life with obstruction clinically confirmed on examination. Antibiotic drops and massage of the lacrimal sac was advised. Probing was carried out for the nonresolving cases at the age of one year, and balloon dilatation for the failed case.
Results: A total of 80 patients with CNLDO were included in the study. Thirty six (45%) of these infants had presented within the first two months of life. Out of these 80 patients 8 patients were lost to follow up. Out of remaining 72 patients, 66 (82.5%) recovered with conservative treatment with topical antibiotics within one year. Only 6 (7.5%) of the patients required probing; success was achieved in five (83.3%) patients and the one who failed was referred for intubation and balloon dilatation at King Hussein Medical Center, Amman.
Conclusion: Spontaneous improvement of CNLDO is the natural course in most patients and probing for unresponsive cases is recommended at one year of age. Keywords: Congenital, Nasolacrimal, Probing Sudan Journal of Medical Sciences Vol. 3 (3) 2008: pp. 219-22
Electron Addition Spectrum in the Supersymmetric t-J Model with Inverse-Square Interaction
The electron addition spectrum A^+(k,omega) is obtained analytically for the
one-dimensional (1D) supersymmetric t-J model with 1/r^2 interaction. The
result is obtained first for a small-sized system and its validity is checked
against the numerical calculation. Then the general expression is found which
is valid for arbitrary size of the system. The thermodynamic limit of
A^+(k,omega) has a simple analytic form with contributions from one spinon, one
holon and one antiholon all of which obey fractional statistics. The upper edge
of A^+(k,omega) in the (k,omega) plane includes a delta-function peak which
reduces to that of the single-electron band in the low-density limit.Comment: 5 pages, 1 figure, accepted for publication in Phys. Rev. Let
Volume XCIV, Number 13, January 24, 1975
WOS: 000187026500009Faunistic analysis of a total of 77 benthic samples collected in different biotopes and depths from northern Cyprus in 1997 and 1998 yielded 36 species and one subspecies of syllid polychaetes belonging to Autolytinae and Exogoninae, of which three species (Exogone (Parexogone) wolfi San Martin, 1991, Sphaerosyllis longipapillata Hartmann-Schroder, 1979 and Sphaerosyllis sp. 2) are new to the Mediterranean, seven species to the eastern Mediterranean, 23 species to the Levantine Sea and 32 species to the Cypriot coast. The morphological, biometrical and distributional features of each species as well as a checklist of species of Autolytinae and Exogoninae reported from the Levant coasts are provided
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