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Tytuł:
Identification of water treatment plant based on feedforward neural network
Autorzy:
Mohamed, A. F.
Radwa, H. Z.
Powiązania:
https://bibliotekanauki.pl/articles/971051.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
water treatment plant
coagulation process
PID
neural network control
Opis:
Coagulation process is the main process in conventional water treatment process sequence. It influences the following treatment process aspects: maintaining plant efficiency and increasing the quality of the produced water. This is accomplished by adding chemicals to raw water, such as alum sulphate. To secure the appropriate plant performance, a mathematical model is proposed in this paper for the coagulation unit, followed by the development of the control strategy. Classic PID and neural network based controller regulating the process are used. Tests were performed, based on the real data for water treatment, using MATLAB/SIMULINK. Simulation results showed better values for both settling time and overshoot in the case of using neural network based controller than PID.
Źródło:
Control and Cybernetics; 2017, 46, 3; 247-258
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Extended finite element numerical analysis of scale effect in notched glass fiber reinforced epoxy composite
Rozszerzona analiza numeryczna metodą elementów skończonych efektu skali w epoksydowym kompozycie z karbem wzmocnionym włóknem szklanym
Autorzy:
Abdellah, M. Y.
Alsoufi, M. S.
Hassan, M. K.
Ghulman, H. A.
Mohamed, A. F.
Powiązania:
https://bibliotekanauki.pl/articles/139922.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
XFEM
extended finite element method
composite laminate
fracture processing zone
crack opening displacement
rozszerzona metoda elementów skończonych
laminat kompozytowy
strefa procesu pęknięcia
przemieszczenie otworu szczeliny
Opis:
Nominal strength reduction in cross ply laminates of [0/90]2s is observed in tensile tests of glass fiber composite laminates having central open hole of diameters varying from 2 to 10 mm. This is well known as the size effect. The extended finite element method (XFEM) is implemented to simulate the fracture process and size effect (scale effect) in the glass fiber reinforced polymer laminates weakened by holes or notches. The analysis shows that XFEM results are in good agreement with the experimental results specifying nominal strength and in good agreement with the analytical results based on the cohesive zone model specifying crack opening displacement and the fracture process zone length.
Zmniejszenie nominalnej wytrzymałości laminatu warstwowego z poprzecznym ułożeniem włókien typu [0/90]2s jest obserwowane dla naprężeń rozciągających w laminatach kompozytowych z włóknem szklanym mających centralny otwór o średnicy od 2 do 10 mm. Jest to dobrze znany efekt rozmiaru (efekt skali). Rozszerzona analiza metodą elementów skończonych (XFEM) została zastosowana w celu symulacji procesu pękania i efektu skali w polimerowych laminatach z włóknem szklanym osłabionych obecnością karbu lub otworu. W pracy wykazano, że wyniki metody XFEM dotyczące wytrzymałości nominalnej są zgodne z danymi eksperymentalnymi, dobrze zgadzają sią z wynikami analitycznymi opartymi na modelu strefy spójnej i pozwalają określić przemieszczenie otworu szczeliny i długość strefy procesu pęknięcia.
Źródło:
Archive of Mechanical Engineering; 2015, LXII, 2; 217-236
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of compression modalities for recovery on wrestlers’ biomarkers in one day tournament
Autorzy:
Ghoraba*a, Mohamed S.
Ghazy, Marwa F.
Powiązania:
https://bibliotekanauki.pl/articles/1030796.pdf
Data publikacji:
2019
Wydawca:
Uniwersytet Szczeciński. Wydawnictwo Naukowe Uniwersytetu Szczecińskiego
Tematy:
Compression modalities
glucose level “GL”
lactic acid “LA”
recovery
serum creatinine “SCR”
wrestling
Opis:
The aim of the study was to investigate the effect of different compression modalities as to recovery enhancement on some biomarkers in wrestlers. Serum creatinine, lactic acid and glucose level were tested in elite wrestlers before a match-up, 3 minutes post-match up and 19 minutes after applying recovery compression model. The results showed insignificant differences between pre-post 3-minutes tests among research groups due to sample equality, 3-minutes and 19-minutes post match up tests showed efficacy of compression technique in enhancing recovery in sake of 160/20 mmHg compression modality with enhancement percentage of 16.614% for serum creatinine, 43.214% for lactic acid and 22.505% for glucose level. The compression band with 160/20 mmHg exceeds recovery after match-up.
Źródło:
Central European Journal of Sport Sciences and Medicine; 2019, 28, 4; 39-52
2300-9705
2353-2807
Pojawia się w:
Central European Journal of Sport Sciences and Medicine
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of foliar application of Sida compound fertilizer on growth, yield, and fruit chemical composition of "Early Superior" grapevine
Autorzy:
Mohamed, A.-R.M.A.
Abdel-Aziz, F.H.
Mohamed, M.A.
Gobara, A.
Powiązania:
https://bibliotekanauki.pl/articles/2087.pdf
Data publikacji:
2013
Wydawca:
Instytut Ogrodnictwa
Tematy:
foliar application
natural fertilizer
growth
vegetative growth
yield
fruit
chemical composition
grape-vine
Early Superior cultivar
leaf mineral content
Źródło:
Journal of Horticultural Research; 2013, 21, 2
2300-5009
Pojawia się w:
Journal of Horticultural Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Prevalence of intestinal parasites among the population of the Gaza Strip, Palestine
Autorzy:
Mezeid, N.
Shaldoum, F.
Al-Hindi, A.I
Mohamed, F.S.A.
Darwish, Z.E.A.
Powiązania:
https://bibliotekanauki.pl/articles/5938.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Parazytologiczne
Tematy:
prevalence
intestinal parasite
parasite
population
health problem
Gaza Strip region
Palestine
Opis:
Intestinal parasitic diseases in Gaza Strip are a significant health problem. The main aim of this study is to determine the prevalence of parasitic infection among patients in the five governorates of the Gaza Strip. A crosssectional parasitological survey was conducted on 600 patients. Stool specimens were examined microscopically for the presence of parasite eggs or larvae/cysts per wet amount by the saline iodine and formol-ether concentration method. Of 600 subjects examined, 245 (40.8%) were infected with one or more intestinal parasites. Entamoeba histolytica/dispar and Giardia lamblia were the most prevalent parasites amongst the population (28.8%), (9.5%). Female patients demonstrated a higher prevalence of intestinal parasitic infections (42.7%) than males (39.0%). However, this difference was not significant (p>0.05). According to occupation, the rate of infection was highest among farmers (56.0%), followed by employers (44.2%) with laborers showing the lowest rate (30.17%). These differences in occupational prevalence were found to be statistically significant (p<0.05). The present study demonstrates that intestinal protozoan infections are still a public health problem in the Gaza strip, with Entamoeba and Giardia infections being most common. Therefore, it is necessary to develop effective prevention and control strategies, including health education and environmental sanitation improvement.
Źródło:
Annals of Parasitology; 2014, 60, 4
0043-5163
Pojawia się w:
Annals of Parasitology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Management of potato virus Y (PVY–NTN) causing potato tuber necrotic ringspot disease (PTNRD) in potato by prior treatment with a mild PVY strain
Autorzy:
Abdalla, O.A.
Eraky, A.I.
Mohamed, S.A.
Fahmy, F.G.
Powiązania:
https://bibliotekanauki.pl/articles/65943.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Egypt
pest management
potato virus Y
potato tuber
necrotic ringspot disease
potato
plant protection
mild strain
treatment
Opis:
Potato virus Y (PVY) is one of the most destructive viruses infecting potato in Egypt and worldwide. Recent research has shown that a necrotic PVY-NTN strain is infecting potato in Upper Egypt. Chemical control is not effective to control this viral pathogen. An alternative to control PVY infecting potato is using a mild PVY strain to elicit systemic cross protection in potato plants against infection with a severe necrotic strain of PVY. Results of this study showed that a PVY necrotic strain produced a significant lesser number of local lesions on diagnostic plants (Robinia pseudoacacia L.) when these plants were treated first with a mild PVY strain. Data obtained from greenhouse and field experiments indicated that treatment of potato plants (variety Burna) with a mild PVY strain significantly protected potato from infection with a severe necrotic PVY strain, and resulted in a significant increase in tuber yield compared with infected plants without prior treatment with a mild PVY strain. The highest increase in potato tuber yield was obtained when potato plants were inoculated with a mild PVY strain 3 days before challenging with the severe necrotic PVY strain. This study proved that using a mild strain of PVY can significantly protect potato plants from infection with a severe strain of this virus under both greenhouse and field conditions and can present a potential method to reduce losses due to infection of this virus in Assiut governorate and Upper Egypt.
Źródło:
Journal of Plant Protection Research; 2018, 58, 2
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exploitation of industrial solid wastes for preparing zeolite as a value-added product and its kinetics as adsorbent for heavy metal ions
Autorzy:
Abdel-Hameed, Reham Mohamed
Abdel-Aal, Elsayed A.
Farghaly, Fatma E.
Ibrahim, Ibrahim A.
Abdel Khalek, Mohamed A.
Ahmed, Mohamed A.
Abdel-Messih, Micheal F.
Powiązania:
https://bibliotekanauki.pl/articles/1448799.pdf
Data publikacji:
2021
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
zeolite P
aluminium wastes
hydrothermal process
metal ion removal
aluminum waste
Opis:
Aluminum and fumed silica as solid industrial wastes were converted to zeolite NaPas a value-addedproduct without any template. The hydrothermal process was optimized using static autoclave. The crystallization was carried out at 100, 120 and 150°C for 24, 48 and 72 h. The prepared zeolite of Si:Al ratio of 1.2 was characterized using X-ray Diffraction (XRD), Scanning Electron Microscope (SEM) provided with Energy Dispersive Spectroscopy (EDS), Surface Area, Fourier Transmitted Infra-Red (FTIR) and Thermal Analysis (TG-DSC). The crystalline phase was formed at 100°Cafter 72 hours and at 120°C after 48 hours, while it was formed after 24 honlyat 150°C. Increasing temperature and time lead to the conversion of the prismatic gibbsite crystals into plate-like structure of zeolitewhich is then formedcauliflower-like structure.The prepared zeolite was employed as adsorbent for $Ni^{2+}$ and $Cu2+ions from aqueous solution.The kinetic studies of adsorption processes were performed.
Źródło:
Physicochemical Problems of Mineral Processing; 2021, 57, 1; 87-99
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Potential toxicity assessment of novel selected pesticides against sand termite, Psammotermes hypostoma Desneux workers (Isoptera: Rhinotermitidae) under field conditions in Egypt
Autorzy:
Ahmed, M.A.I.
Eraky, E.-S.A.
Mohamed, M.F.
Soliman, A.-A.S.
Powiązania:
https://bibliotekanauki.pl/articles/66459.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Opis:
The sand termite, Psammotermes hypostoma Desneux is a major pest in the New Valley Governorate, Egypt. Great efforts have been taken to control the pest. We evaluated the toxicity of four selected neonicotinoids [acetamiprid (20% SP), imidacloprid (20% SL), thiamethoxam (18.6% SC), and thiamethoxam (40% WG)], and one organophosphate pesticide [chlorpyrifos (48% EC)] against P. hypostoma workers. The investigation was done under field conditions, using the palm fronds method. However, the reduction percentages in palm fronds was recorded as the height of the sandy clay formed by termite workers on palm frond surfaces, when the fronds had been treated with a different concentration of each pesticide. The results were recorded after 15, 30, 45, and 60 days. Chlorpyrifos (48% EC) was considered the most potent pesticide among all the pesticides tested, but acetamiprid (20% SP) was considered the most toxic among the neonicotinoid pesticides tested. Moreover, the formulation of thiamethoxam (18.6% SC) was more powerful than thaimethoxam (40% WG). Furthermore, the reduction percentages on palm fronds increased significantly with an increase of the exposure period (from 15 to 60 days), as a result of the surface foraging activity of the sand termite workers. These results are given as unique and encouraging trends in controlling sand termites in Egypt.
Źródło:
Journal of Plant Protection Research; 2015, 55, 2
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A FCG Model and the Graphical User Interface Under Matlab for Predicting Fatigue Life: Parametric Studies
Autorzy:
Kebir, Tayeb
Correia, José A.F.O.
Benguediab, Mohamed
Imad, Abdellatif
Powiązania:
https://bibliotekanauki.pl/articles/2105193.pdf
Data publikacji:
2021
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
fatigue life prediction
Graphical User Interface
fatigue crack growth
cyclic hardening
Paris
Walker
Forman
Opis:
The focus of this research work was predicting the fatigue life of mechanical components used for industrial and transport systems. To understand how the phenomenon of fatigue occurs in a material, the fatigue crack growth is studied. The purpose of this work was to create a graphical user interface (GUI) under Matlab to allow researchers to conduct the parametric studies of fatigue crack propagation to predict fatigue life. In this work, three models for fatigue crack propagation were used: those of Paris, Walker and Forman in order to study the three parameters: the Paris exponent m, load ratio R and hardness KIC, respectively. In addition, a novel model FCG was developed to study the influence of the hardening parameters (K′, n′) on fatigue crack propagation. The comparison of the simulation results with those in the literature shows good agreement.
Źródło:
Fatigue of Aircraft Structures; 2021, 13; 116--139
2081-7738
2300-7591
Pojawia się w:
Fatigue of Aircraft Structures
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Quality assessment of the essential oil from Eucalyptus globulus Labill of Blida (Algeria) origin
Autorzy:
Boukhatem, M. N.
Amine, F. M.
Kameli, A.
Saidi, F.
Walid, K.
Mohamed, S. B.
Powiązania:
https://bibliotekanauki.pl/articles/411538.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Eucalyptus globulus Labill
Chemical composition
Essential oil
Gas Chromatography
Eucalyptol
Opis:
Despite the reputation earned by aromatic and medicinal plants of Algeria, the chemical constituents of Eucalyptus globulus essential oil (EGEO) of Blida origin has not previously been investigated. Thus, the present study has been conducted for the determination of chemical constituents and different physico-chemical properties of the EGEO. Chemical composition of the EGEO, grown in Algeria, was analysed by Gas Chromatography-Mass Spectrometry. The chemical components were identified on the basis of Retention Time and comparing with mass spectral database of standard compounds. Relative amounts of detected compounds were calculated on the basis of GC peak areas. Fresh leaves of E. globulus on steam distillation yielded 0.96 % (v/w) of essential oil whereas the analysis resulted in the identification of a total of 11 constituents, 1.8 cineole (85.8 %), α-pinene (7.2 %), and β-myrcene (1.5 %) being the main components. Other notable compounds identified in the oil were β-pinene, limonene, α-phellandrene, γ-terpinene, linalool, pinocarveol, terpinen-4-ol, and α-terpineol. The physical properties such as specific gravity, refractive index and optical rotation and the chemical properties such as saponification value, acid number and iodine number of the EGEO were examined. The oil extracted has been analyzed to have 1.4602 - 1.4623 refractive index value, 0.918 - 0.919 specific gravity (sp.gr.), +9 - +10 optical rotation that satisfy the standards stipulated by European Pharmacopeia. All the physical and chemical parameters were in the range indicated by the ISO standards. Our findings will help to access the quality of the Eucalyptus oil which is important in the production of high value essential oils that will help to improve the economic condition of the community as well as the nation.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 17, 3; 303-315
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A two-stage stochastic programming approach for production planning system with seasonal demand
Autorzy:
Mahmoud, Asmaa A.
Aly, Mohamed F.
Mohib, Ahmed M.
Afefy, Islam H.
Powiązania:
https://bibliotekanauki.pl/articles/952860.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
process manufacturing system
two-stage stochastic programming
sampling average approximation
Opis:
Seasonality is a function of a time series in which the data experiences regular and predictable changes that repeat each calendar year. Two-stage stochastic programming model for real industrial systems at the case of a seasonal demand is presented. Sampling average approximation (SAA) method was applied to solve a stochastic model which gave a productive structure for distinguishing and statistically testing a different production plan. Lingo tool is developed to obtain the optimal solution for the proposed model which is validated by Math works Matlab. The actual data of the industrial system; from the General Manufacturing Company, was applied to examine the proposed model. Seasonal future demand is then estimated using the multiplicative seasonal method, the effect of seasonality was presented and discussed. One might say that the proposed model is viewed as a moderately accurate tool for industrial systems in case of seasonal demand. The current research may be considered a significant tool in case of seasonal demand. To illustrate the applicability of the proposed model a numerical example is solved using the proposed technique. ANOVA analysis is applied using MINITAB 17 statistical software to validate the obtained results.
Źródło:
Management and Production Engineering Review; 2020, 11, 1; 31--42
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adjustment to target debt maturity and equity mispricing : evidence from Asia Pacific
Dostosowanie do docelowej wymagalności zadłużenia oraz nieprawidłowej wyceny wartości : dowody z Azji i Pacyfiku
Autorzy:
Hussain, H. I.
Hadi, A. R. A.
Mohamed-Isa, A.
Salem, M. A.
Kamarudin, F.
Jabarullah, N. H.
Powiązania:
https://bibliotekanauki.pl/articles/404704.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska
Tematy:
debt maturity
target adjustment behavior
speed of adjustment
capital structure
Asia Pacific region
dojrzałość długu
zachowanie dostosowania celu
szybkość dostosowań
struktura kapitałowa
region Azji i Pacyfiku
Opis:
This paper examines firms’ target adjustment behavior for debt maturity structure for selected countries from the Asia Pacific region. The literature documents that managers’ structure debt issues in line with a target maturity structure which is limited by transactions costs, information asymmetry, agency problems, liquidity needs as well as institutional factors. Our paper contends that firms adjust to target levels at differing rates based on whether the current maturity structure is above or below target levels as well as equity mispricing. We estimate the target debt maturity based on the lead level and measure speed of adjustment to target levels by regressing the difference between the simulated and actual values. Our findings indicate that firms which are below target debt maturity tend to adjust at more rapid rates during periods of overvaluation. Firms which are above target debt maturity tend to adjust at more rapid rates during periods of undervaluation. Our findings indicate asymmetric adjustment rates indicating that debt maturity structure serves as an important tool for signaling. The implications provide a better understanding on the impact of debt maturity on information asymmetry leading to differences in adjustment to target debt maturity structures.
W niniejszym artykule przeanalizowano zachowanie firm w zakresie dostosowań docelowych dla struktury zapadalności długu dla wybranych krajów z regionu Azji i Pacyfiku. W literaturze udokumentowano, że struktura zarządzania zadłużeniem jest zgodna z docelową strukturą zapadalności, która jest ograniczona przez koszty transakcji, asymetrię informacji, problemy agencji, potrzeby płynności oraz czynniki instytucjonalne. Stwierdzono, że firmy dostosowują się do poziomów docelowych przy różnych stawkach w zależności od tego, czy obecna struktura zapadalności jest powyżej lub poniżej poziomu docelowego, jak również z powodu niewłaściwej wyceny kapitału własnego. Oszacowano docelowy termin zapadalności długu na podstawie poziomu wiodącego oraz zmierzono szybkość dostosowania do poziomów docelowych poprzez regresję różnicy między symulowanymi a rzeczywistymi wartościami. Wyniki wskazują, że firmy, które nie osiągają docelowego poziomu zadłużenia, mają tendencję do szybszego dostosowywania stawek w okresach przewartościowania. Firmy, które przekraczają docelowy poziom zadłużenia, mają tendencję do szybszego dostosowywania stawek w okresach niedowartościowania. Wyniki wskazują na asymetryczne wskaźniki korygowania, które wskazują, że struktura terminów zapadalności służy jako ważne narzędzie sygnalizacji. Implikacje te zapewniają lepsze zrozumienie wpływu dojrzałości długu na asymetrię informacyjną prowadzącą do różnic w dostosowaniu do docelowych struktur zapadalności długu.
Źródło:
Polish Journal of Management Studies; 2018, 17, 2; 87-100
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A proposed preamble channel estimation scheme for flip FBMC-based indoor VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2063904.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
channel estimation
filter bank multicarrier
IEEE 802.15.7 standard
interference approximation method
visible light communication
Opis:
Filter bank multicarrier waveform is investigated as a potential waveform for visible light communication broadcasting systems. Imaginary inter-carrier and/or inter-symbol interference are causing substantial performance degradation in the filter bank multicarrier system. Direct current-biased optical filter bank multicarrier modulation overcomes all the problems of direct current-biased optical-orthogonal frequency division multiplexing modulation approaches in terms of speed and bandwidth. However, it also wastes a lot of energy while transforming a true bipolar signal into a positive unipolar signal by adding direct current-bias. In this paper, a flip-filter bank multicarrier-based visible light communication system was introduced to overcome this problem. In this system, a bipolar signal is converted to a unipolar signal by isolating the positive and negative parts, turning them to positive and then delivering the signal. Also, a new channel estimation scheme for a flip-filter bank multicarrier system is proposed which improves the channel estimation performance compared to that of each of the conventional schemes. The proposed system performance is measured in terms of bit error rate, normalized mean squared error, and constellation diagram. The superiority of the proposed scheme over other conventional structures has been successfully verified by MATLAB 2020b simulation experiments results. These results are evaluated under indoor visible light communication standard.
Źródło:
Opto-Electronics Review; 2022, 30, 1; art. no. e140859
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid PAPR reduction schemes for different OFDM-based VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174839.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
peak-to-average power ratio
bit error rate
Opis:
Orthogonal frequency division multiplexing has been widely used in many radio frequency wireless communication standards as a preferable multicarrier modulation scheme. The modulated signals of a conventional orthogonal frequency division multiplexing system are complex and bipolar. In intensity-modulated direct detection optical wireless communications, transmitted signals should be real and unipolar due to non-coherent emissions of an optical light emitting diode. In this paper, different hybrid optical systems have been proposed to satisfy real and unipolar signals. Peak-to-average power ratio is one of the biggest challenges for orthogonal frequency division multiplexing-based visible light communications. They are based on a combination of non-linear companding techniques with spreading or precoding techniques. Simulation evaluation is performed under direct current-biased optical orthogonal frequency division multiplexing, asymmetrically clipped optical orthogonal frequency division multiplexing, and Flip-orthogonal frequency division multiplexing systems in terms of peak-to-average power ratio, bit error rate, and spectral efficiency. The proposed schemes are investigated to determine a scheme with a low peak-to-average power ratio and an acceptable bit error rate. MATLABTM software has been successfully used to show the validity of the proposed schemes.
Źródło:
Opto-Electronics Review; 2022, 30, 3; art. no. e141951
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Hybrid PAPR reduction schemes for different OFDM-based VLC systems
Autorzy:
El-Ganiny, Mohamed Y.
Khalaf, Ashraf A. M.
Hussein, Aziza I.
Hamed, Hesham F. A.
Powiązania:
https://bibliotekanauki.pl/articles/2174840.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
peak-to-average power ratio
bit error rate
Opis:
Orthogonal frequency division multiplexing has been widely used in many radio frequency wireless communication standards as a preferable multicarrier modulation scheme. The modulated signals of a conventional orthogonal frequency division multiplexing system are complex and bipolar. In intensity-modulated direct detection optical wireless communications, transmitted signals should be real and unipolar due to non-coherent emissions of an optical light emitting diode. In this paper, different hybrid optical systems have been proposed to satisfy real and unipolar signals. Peak-to-average power ratio is one of the biggest challenges for orthogonal frequency division multiplexing-based visible light communications. They are based on a combination of non-linear companding techniques with spreading or precoding techniques. Simulation evaluation is performed under direct current-biased optical orthogonal frequency division multiplexing, asymmetrically clipped optical orthogonal frequency division multiplexing, and Flip-orthogonal frequency division multiplexing systems in terms of peak-to-average power ratio, bit error rate, and spectral efficiency. The proposed schemes are investigated to determine a scheme with a low peak-to-average power ratio and an acceptable bit error rate. MATLABTM software has been successfully used to show the validity of the proposed schemes.
Źródło:
Opto-Electronics Review; 2022, 30, 3; art. no. e141951
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
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