260 research outputs found
Solutions to Integrals Involving the Marcum Q-Function and Applications
Novel analytic solutions are derived for integrals that involve the
generalized Marcum Q-function, exponential functions and arbitrary powers.
Simple closed-form expressions are also derived for the specific cases of the
generic integrals. The offered expressions are both convenient and versatile,
which is particularly useful in applications relating to natural sciences and
engineering, including wireless cpmmunications and signal processing. To this
end, they are employed in the derivation of the channel capacity for fixed rate
and channel inversion in the case of correlated multipath fading and switched
diversity.Comment: 15 Pages, 2 Figure
Characterization of energetically functional inverted membrane vesicles from Corynebacterium glutamicum
AbstractWe show that inverted membrane vesicles from Corynebacteriwn glutamicum, a Gram-positive bacterium, are able to generate and maintain an electrochemical gradient of protons in response to the addition of NADH. This result indicates that the respiratory chain is intact and that the vesicles are reasonably impermeable to protons. These membrane vesicles may be the starting point for in vitro translocation studies of proteins in Gram-positive bacteria
Optical Asymmetric Modulation for VLC Systems
The explosive growth of connected devices and the increasing number of broadband users have led to an unprecedented growth in traffic demand. To this effect, the next generation wireless systems are envisioned to meet this growth and offer a potential data rate of 10 Gbps or more. In this context, an attractive solution to the current spectrum crunch issue is to exploit the visible light spectrum for the realization of high-speed commutation systems. However, this requires solutions to certain challenges relating to visible light communications (VLC), such as the stringent requirements of VLC-based intensity modulation and direct detection (IM/DD), which require signals to be real and unipolar. The present work proposes a novel power-domain multiplexing based optical asymmetric modulation (OAM) scheme for indoor VLC systems, which is particularly adapted to transmit high-order modulation signals using linear real and unipolar constellations that fit into the restrictions of IM/DD systems. It is shown that the proposed scheme provides improved system performance that outperforms alternative modulation schemes, at no extra complexity
Optical Non-Orthogonal Multiple Access for Visible Light Communication
The proliferation of mobile Internet and connected devices, offering a
variety of services at different levels of performance, represents a major
challenge for the fifth generation wireless networks and beyond. This requires
a paradigm shift towards the development of key enabling techniques for the
next generation wireless networks. In this respect, visible light communication
(VLC) has recently emerged as a new communication paradigm that is capable of
providing ubiquitous connectivity by complementing radio frequency
communications. One of the main challenges of VLC systems, however, is the low
modulation bandwidth of the light-emitting-diodes, which is in the megahertz
range. This article presents a promising technology, referred to as "optical-
non-orthogonal multiple access (O-NOMA)", which is envisioned to address the
key challenges in the next generation of wireless networks. We provide a
detailed overview and analysis of the state-of-the-art integration of O-NOMA in
VLC networks. Furthermore, we provide insights on the potential opportunities
and challenges as well as some open research problems that are envisioned to
pave the way for the future design and implementation of O-NOMA in VLC systems
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Efficiently injecting spin-polarized current into semiconductors by interfacing crystalline ferromagnetic oxides directly on the semiconductor material
A spintronic device and a method for making said spintronic device. The spintronic device includes an epitaxial crystalline ferromagnetic oxide formed directly on the semiconductor material thereby allowing spin-polarized current to be efficiently injected from the ferromagnetic oxide into the semiconductor material. A host crystal lattice includes multiple sets of stacked oxide layers of material A and B of a perovskite structure with a formula of ABO3. After an oxide layer of B is grown, magnetic ions are introduced to intermix with the B material, which may replace some of the ions of the B material. The process of growing additional stacked oxide layers of material A and B and introducing further magnetic ions after the deposition of the oxide layer of B continues until enough magnetic ions are sufficiently close to one another that they align in the same direction thereby forming a ferromagnetic oxide on the semiconductor material.Board of Regents, University of Texas Syste
Performance Analysis of Coherent and Noncoherent Modulation under I/Q Imbalance
In-phase/quadrature-phase Imbalance (IQI) is considered a major
performance-limiting impairment in direct-conversion transceivers. Its effects
become even more pronounced at higher carrier frequencies such as the
millimeter-wave frequency bands being considered for 5G systems. In this paper,
we quantify the effects of IQI on the performance of different modulation
schemes under multipath fading channels. This is realized by developing a
general framework for the symbol error rate (SER) analysis of coherent phase
shift keying, noncoherent differential phase shift keying and noncoherent
frequency shift keying under IQI effects. In this context, the moment
generating function of the signal-to-interference-plus-noise-ratio is first
derived for both single-carrier and multi-carrier systems suffering from
transmitter (TX) IQI only, receiver (RX) IQI only and joint TX/RX IQI.
Capitalizing on this, we derive analytic expressions for the SER of the
different modulation schemes. These expressions are corroborated by comparisons
with corresponding results from computer simulations and they provide insights
into the dependence of IQI on the system parameters. We demonstrate that the
effects of IQI differ considerably depending on the considered system as some
cases of single-carrier transmission appear robust to IQI, whereas
multi-carrier systems experiencing IQI at the RX require compensation in order
to achieve a reliable communication link
Biochemical Features of Nonalcholic Hepatosteatosis
In this study we investigated the biochemical features of patients withNASH in Southestern Anatolia. One hundered and two patients wereincluded in the study (mean age 42.1; 52 (51%) female, 50 (49%) male).Fifty six patients were overweight, 27 were obese and 2 were morbid obese.Out of 102 patients 34 were in steatohepatitis group. Median AST level was34.6 U/L and ALT was 51.9 U/L. Tehre was diabetes mellitus in 15 patients.Obesity, hyperlipidemia and diabetes mellituswere important risk factors forNASH in our region. Steatohepatitis was more comman in male group. Inconclusion patients with hepatosteatosis must be evaluated with respect tosteatohepatitis and, if necessary, must be treated
Antifungal and Bioherbicidal Properties of Essential Oils of Thymus fallax Fish & Mey., Origanum vulgare L. and Mentha dumetorum Schult.
WOS: 000343767000048The chemical composition of the essential oils obtained from the aerial parts of Thymus fallax, Origanum vulgare and Mentha dumetorum was analyzed by gas chromatography-mass spectrometry and the following were found to be the main constituents: T. fallax-thymol (41.48 %), o-cymene (26.75 %), zeta-terpinen (15.84 %), 2-isopropyl-1-methoxy-4-methylbenzene (5.10 %), terpineolene (2.11 %) and carvacrol (1.28 %); O. vulgare-thymol (50.41 %), carvacrol (12.96 %), 2-bornene (11.28 %), zeta-terpinen (8.80 %), o-cymene (6.68 %), alpha-bisabolane (2.19 %) and caryophyllene (1.31 %); and M. dumetorum-carvone (39.64 %), eucalyptol (14.34 %), dihydrocarvone (12.78 %), limonene (7.79 %). The antifungal activities of the oils against Alternaria solani, Fusarium oxysporum and Rhizoctonia solani were also evaluated and were found to be toxic to the pathogens. The results revealed that essential oils, especially those of T. fallax and O. vulgare, had a strong antifungal activity with a significant inhibition on the growth of the 3 tested fungi. In contrast, the M. dumetorum oil did not inhibit the growth of Rhizoctonia solani and also exerted a limited inhibitory effect on the mycelial growth of the other two fungi tested. The results of herbicidal assays using these essential oils against four different plant species, Abutilon theophrasti Medik., Agrostemma githago L., Medicago sativa L. and Lepidium sativum L., showed that the oils had inhibitory effects on seed germination and seedling growth. The findings of the present study confirmed that plant essential oils can be used as natural herbicides and fungicides to control weeds and pathogenic fungi, thus, reducing the dependence on synthetic pesticides
Effect of Styrene Butadiene Rubber Latex on Mechanical Properties of Eco Concrete: Limestone Powder Concrete
To make concrete a truly green material, viable cement substitutes are available. This experimental investigation is performed to study the effect of using limestone powder (LSP) and styrene butadiene rubber (SBR) latex in the concrete mix. In this work, a concrete with 1:1.8:3 cementitious material:sand:gravel and water/cement ratio w/c of 0.5 is produced. First, LSP is used with 0, 5, 10, 15, and 20% replacements by weight of cements. The fineness of the LSP is measured using sieve No. 200 and showed about 30% pass. Second, and to improve the matrix of concrete due to the dilution effect, four ratios of SBR latex (0, 5, 10, and 15%) are added by weight of cements to the mix for each LSP ratio. Compressive strength at ages of 3, 7, 14, 28, and 90 days is tested for the concrete specimens mixed with LSP only to examine its effect on concrete strength’s development with time, whereas strengths are recorded at the age of 28 days for the other concretes. Three prisms were cast for each ratio and tested at 28 days. The results show general improvements in terms of compressive and flexural strengths
ANN Car Mileage per Gallon Prediction
In this paper an Artificial Neural Network (ANN) model was used to help cars dealers
recognize the many characteristics of cars, including manufacturers, their location and
classification of cars according to several categories including: Make, Model, Type,
Origin, DriveTrain, MSRP, Invoice, EngineSize, Cylinders, Horsepower, MPG_Highway,
Weight, Wheelbase, Length. ANN was used in prediction of the number of miles per
gallon when the car is driven in the city(MPG_City). The results showed that ANN model
was able to predict MPG_City with 97.50 % accuracy. The factor of DriveTrain has the
most influence on MPG_City evaluation. Similar studies can be carried out for the
evaluation of other characteristics of cars
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