9,040 research outputs found
Compensating Chromatic Dispersion and Phase Noise using Parallel AFB-MBPS For FBMC-OQAM Optical Communication System
Filter Bank Multi-Carrier Offset-QAM (FBMC-OQAM) is one of the hottest topics in research for 5G multi-carrier methods because of its high efficiency in the spectrum, minimal leakage in the side lobes, zero cyclic prefix (CP), and multiphase filter design. Large-scale subcarrier configurations in optical fiber networks need the use of FBMC-OQAM. Chromatic dispersion is critical in optical fiber transmission because it causes different spectral waves (color beams) to travel at different rates. Laser phase noise, which arises when the phase of the laser output drifts with time, is a major barrier that lowers throughput in fiber-optic communication systems. This deterioration may be closely related among channels that share lasers in multichannel fiber-optic systems using methods like wavelength-division multiplexing with frequency combs or space-division multiplexing. In this research, we use parallel Analysis Filter Bank (AFB) equalizers in the receiver part of the FBMC OQAM Optical Communication system to compensate for chromatic dispersion (CD) and phase noise (PN). Following the equalization of CD compensation, the phase of the carriers in the received signal is tracked and compensated using Modified Blind Phase Search (MBPS). The CD and PN compensation techniques are simulated and analyzed numerically and graphically to determine their efficacy. To evaluate the FBMC\u27s efficiency across various equalizers, 16-OQAM is taken into account. Bit Error Rate (BER), Optical Signal-to-Noise Ratio (OSNR), Q-Factor, and Mean Square Error (MSE) were the primary metrics we utilized to evaluate performance. Single-tap equalizer, multi-tap equalizer (N=3), ISDF equalizer with suggested Parallel Analysis Filter Banks (AFBs) (K=3), and MBPS were all set aside for comparison. When compared to other forms of Nonlinear compensation (NLC), the CD and PN tolerance attained by Parallel AFB equalization with MBPS is the greatest
Two-Parameters Bifurcation in Quasilinear Dierential-Algebraic Equations
In this paper, bifurcation of solution of guasilinear dierential-algebraic equations (DAEs) is studied. Whereas basic principle that quasilinear DAE is eventually reducible to an ordinary dierential equation (ODEs) and that this reduction so we can apply the classical bifurcation theory of the (ODEs). The taylor expansion applied to the reduced DAEs to prove that is equivalent to an ODE which is a normal form under some non-degeneracy conditions theorems given in this work deal with the saddle node,transcritical and pitchfork bifurcation with two-parameters. Some illustrated examples are given to explain the idea of the paper
Undiagnosed asymptomatic second trimester broad ligament ectopic pregnancy: a case report and mini-review
Pregnancy in the broad ligament is a retro-peritoneal abdominal pregnancy. It is a rare form in which the gestational tissue gets implanted between the layers of the broad ligament. Due to its rarity, the diagnosis is infrequently established before surgical intervention. A twenty-five year old nulliparous woman presented for routine antenatal care in the second trimester (±17 weeks). Routine ultrasound revealed an empty uterus with a large pelviabdominal mass. This picture suggested and undiagnosed extra-uterine pregnancy. A right broad ligament ectopic pregnancy was diagnosed at exploratory laparotomy, excision of pregnancy and right salpingectomy was performed. Postoperative course was uneventful and serum hCG was undetectable at the fourth week after surgery. Information about this rare form of ectopic pregnancy is observational and mainly comes from reported cases. A high index of suspicion is needed for early diagnosis and intervention
Influence of Different Abutment Designs on the Biomechanical Behavior of One-Piece Zirconia Dental Implants and Their Surrounding Bone: A 3D-FEA
Background: In a dental implant/bone system, the design factors affect the value and distributions of stress and deformations that plays a pivotal role on the stability, durability and lifespan of the implant/bone system
Undiagnosed asymptomatic second trimester broad ligament ectopic pregnancy: a case report and mini-review
Pregnancy in the broad ligament is a retro-peritoneal abdominal pregnancy. It is a rare form in which the gestational tissue gets implanted between the layers of the broad ligament. Due to its rarity, the diagnosis is infrequently established before surgical intervention. A twenty-five year old nulliparous woman presented for routine antenatal care in the second trimester (±17 weeks). Routine ultrasound revealed an empty uterus with a large pelviabdominal mass. This picture suggested and undiagnosed extra-uterine pregnancy. A right broad ligament ectopic pregnancy was diagnosed at exploratory laparotomy, excision of pregnancy and right salpingectomy was performed. Postoperative course was uneventful and serum hCG was undetectable at the fourth week after surgery. Information about this rare form of ectopic pregnancy is observational and mainly comes from reported cases. A high index of suspicion is needed for early diagnosis and intervention
Improvement of Unconfined Compressive Strength of Natural Organic Soil
The aim of this paper is to investigate the possible improvement of unconfined compressive strength of natural organic soil by using cement dust and fly ash. Natural organic soil with different percentage of organic content (0, 5, 10.15 and 20 %) is used. Three different percentages of cement dust and fly ash (3, 6 and 9 %) are used to improve the strength characteristics of the organic soil. The effect of curing time is investigates. The result show that unconfined compressive strength of organic soil decreased with increasing the organic content. The addition of cement dust increased the unconfined compressive strength for all percentage of organic content, while the addition of fly ash improved the strength characteristics of organic soil for samples with organic content greater than 10 %. Keywords: organic content, unconfined compressive strength, cement dust, fly ash
Newly Discovered RR Lyrae Stars in the SDSSXPanXSTARRS1XCatalina Footprint
We present the detection of 6,371 RR Lyrae (RRL) stars distributed across
~14,000 deg^2 of the sky from the combined data of the Sloan Digital Sky Survey
(SDSS), the Panoramic Survey Telescope and Rapid Response System 1 (PS1), and
the second photometric catalogue from the Catalina Survey (CSDR2), out of
these, ~2,021 RRL stars (~572 RRab and 1,449 RRc) are new discoveries. The RRL
stars have heliocentric distances in the 4--28 kpc distance range. RRL-like
color cuts from the SDSS and variability cuts from the PS1 are used to cull our
candidate list. We then use the CSDR2 multi-epoch data to refine our sample.
Periods were measured using the Analysis of Variance technique while the
classification process is performed with the Template Fitting Method in
addition to the visual inspection of the light curves. A cross-match of our RRL
star discoveries with previous published catalogs of RRL stars yield
completeness levels of ~50% for both RRab and RRc stars, and an efficiency of
~99% and ~87% for RRab and RRc stars, respectively. We show that our method for
selecting RRL stars allows us to recover halo structures. The full lists of all
the RRL stars are made publicly available.Comment: 14 pages, 11 figures. Accepted 2014 March 30. Received 2014 March 12;
in original form 2013 November 2
Interleaved High Step-up DC-DC Converter with Diode-Capacitor Multiplier Cell and Ripple-Free Input Current
In this paper interleaving and switched-capacitor techniques are used to introduce a high step-up DC-DC converter for renewable energy systems application. The proposed converter delivers high voltage gain without utilizing transformer or excessive duty cycle and features ripple-free input current which results in lower conduction losses and decreased electromagnetic interference (EMI). Lower output capacitance is another advantage of proposed converter, leading to smaller size and lower cost. Furthermore lower voltage stress on switches allows the utilization of switches with low resistance. Simulation results verify the performance of suggested converter
Scale-free equilibria of self-gravitating gaseous disks with flat rotation curves
We introduce exact analytical solutions of the steady-state hydrodynamic
equations of scale-free, self-gravitating gaseous disks with flat rotation
curves. We express the velocity field in terms of a stream function and obtain
a third-order ordinary differential equation (ODE) for the angular part of the
stream function. We present the closed-form solutions of the obtained ODE and
construct hydrodynamical counterparts of the power-law and elliptic disks, for
which self-consistent stellar dynamical models are known. We show that the
kinematics of the Large Magellanic Cloud can well be explained by our findings
for scale-free elliptic disks.Comment: AAS preprint format, 21 pages, 8 figures, accepted for publication in
The Astrophysical Journa
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