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Tytuł:
Ranking new comers to work based on commitment propensity through hybrid method of AHP and TOPSIS
Autorzy:
Safari, H.
Cabrita, M. R.
Hesan, M.
Maleki, M.
Mirzaeirabore, F.
Powiązania:
https://bibliotekanauki.pl/articles/407151.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
AHP
organizational commitment
personality traits
Structural Equation Modelling
TOPSIS
Opis:
This research provides a tool to select and prioritize new comers to work based on their preentry organizational commitment propensity through examining links between the big five personality factors: extroversion, agreeableness, conscientiousness, neuroticism, openness; and three component model of organizational commitment: affective commitment, continues commitment, normative commitment. Findings show that extroversion and openness respectively have positive and negative effects on all three components of organizational commitment. Results gained by Structured Equation Modelling (SEM) indicate neuroticism is negatively related to affective and continues commitment and positively to conscientiousness effects on continues commitment. In the second part of the study, the received results are applied to extract the general equations that enables to estimate new comer’s pre-entry organizational commitment and to rank them using TOPSIS and AHP. The AHP is used to determine the relative weights of commitment criteria and TOPSIS is employed for the final ranking of new comers based on these criteria’s.
Źródło:
Management and Production Engineering Review; 2018, 9, 4; 86-95
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hybrid method for the optimal reactive power dispatch and the control of voltagesin an electrical energy network
Autorzy:
Benchabira, Aissa
Khiat, Mounir
Powiązania:
https://bibliotekanauki.pl/articles/140740.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
electrical energy network
interior point method (IPM)
optimal reactive power dispatch (ORPD)
particle swarm optimization (PSO)
Opis:
This paper presents the resolution of the optimal reactive power dispatch (ORPD) problem and the control of voltages in an electrical energy system by using a hybrid algorithm based on the particle swarmoptimization (PSO) method and interior point method (IPM). The IPM is based on the logarithmic barrier (LB-IPM) technique while respecting the non-linear equality and inequality constraints. The particle swarmoptimization-logarithmic barrier-interior point method (PSO-LB-IPM) is used to adjust the control variables, namely the reactive powers, the generator voltages and the load controllers of the transformers, in order to ensure convergence towards a better solution with the probability of reaching the global optimum. The proposed method was first tested and validated on a two-variable mathematical function using MATLAB as a calculation and execution tool, and then it is applied to the ORPD problem to minimize the total active losses in an electrical energy network. To validate the method a testwas carried out on the IEEE electrical energy network of 57 buses.
Źródło:
Archives of Electrical Engineering; 2019, 68, 3; 535-551
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Innovation in the process of thermal spraying coatings
Autorzy:
Szczucka-Lasota, B.
Powiązania:
https://bibliotekanauki.pl/articles/353980.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
control structure of the coating
local and selective cooling
hybrid method
Opis:
In this paper, the hybrid method connects the ultrasonic spraying method with a injector of complex cooling micro-jet system is presented. The use of properly constructed injector allows for local and selective cooling of the coating structure immediately after spraying process. The construction of injector is the subject of patent in Polen. The presented new technology gives practical possibility of control of coatings structure. This is the kind of positive feedback between the technology process and obtained product (the quality of the process increases the quality of the final product). The initial experimental investigations, presented in this paper, show, that the obtained coatings structure is: fine-dispersion of the grain, with a lower porosity, good compactness and adhesion to the substrate.
Źródło:
Archives of Metallurgy and Materials; 2016, 61, 3; 1431-1436
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The characteristics of the possibility of the use of polymer membranes in production of oxygen for energy processes
Charakterystyka możliwości wykorzystania membran polimerowych do produkcji tlenu dla procesów energetycznych
Autorzy:
Kotowicz, J.
Berdowska, S.
Powiązania:
https://bibliotekanauki.pl/articles/172893.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
membrana polimerowa
produkcja tlenu
proces kriogeniczny
metoda hybrydowa
Aspen
polymeric membrane
oxygen production
cryogenic process
hybrid method
Opis:
In this paper, different methods of oxygen production are characterized. The main attention is focused on the use of polymer membranes. Hybrid method is proposed in the process of oxygen production. Membrane is used in the first stage of this method, while in the second one, the cryogenic process is chosen. The calculations of the membrane parameters have been made in Aspen software. The characteristic values for the membrane separation process such as oxygen recovery rate and permeate purity have been determined. Various systems have been analyzed. It has been calculated that energy consumption in the process of cryogenic oxygen production reaches 0.2 kWh/kgO2 or even 0.19 kWh/kgO2 in the membrane process using a vacuum pump, and in the near future, with the improvement of the membrane properties it will be limited to 0.15 kWh/kgO2.
W artykule scharakteryzowano różne metody produkcji tlenu. Główną uwagę skupiono na wykorzystaniu membran polimerowych. W procesie produkcji tlenu zaproponowano metodę hybrydową, w której w pierwszym stopniu stosuje się membranę, zaś w drugim proces kriogeniczny. Obliczenia membran wykonano przy wykorzystaniu programu Aspen. Wyznaczono charakterystyczne wielkości dla procesu separacji membranowej takie jak stopień odzysku tlenu i czystość permeatu. Analizowano różne układy. Obliczono, że przy zastosowaniu pompy próżniowej w procesie membranowym energochłonność kriogenicznego procesu wytwarzania tlenu może wynieść 0,2 kWh/kgO2 lub nawet 0,19 kWh/kgO2, zaś w najbliższej przyszłości wraz z polepszeniem się właściwości membran może być ograniczona do 0,15 kWh/kgO2.
Źródło:
Archiwum Energetyki; 2012, 42, 3/4; 57-70
0066-684X
Pojawia się w:
Archiwum Energetyki
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modelling of systems of collecting electrodes of electrostatic precipitators by means of the rigid finite element method
Modelowanie układów płyt zbiorczych elektrofiltrów z wykorzystaniem metody sztywnych elementów skończonych
Autorzy:
Adamiec-Wójcik, I.
Powiązania:
https://bibliotekanauki.pl/articles/140060.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
strącanie elektrostatyczne
metoda sztywnych elementów skończonych
metoda hybrydowa
analiza drgań
electrostatic precipitation
rigid finite element method
hybrid method
vibration analysis
Opis:
The paper presents a model of a rapping system of an electrostatic precipitator. The rapping system consists of a set of collecting electrodes hanging on a suspension bar and braced together in a brushing bar. The suspension and brushing bars are modeled using the rigid finite element method, while the collecting plates are modeled using the hybrid method. The method combines the rigid finite element method with the classical finite element method. As a result, the mass matrix is diagonal. Some results of numerical simulations concerning free vibrations of the collecting plates and the influence of the number of elements, into which the plate is divided, on the vibrations of the rapping system are presented.
W artykule przedstawiono model układu strzepującego elektrofiltru suchego. Układ strzepujący składa się z zestawu elektrod zbiorczych zawieszonych na belce górnej i ujętych w drąg strzepujący. Belki górna i dolna modelowane są przy pomocy metody sztywnych elementów skończonych podczas gdy do modelowania elektrod zbiorczych wykorzystywana jest hybrydowa metoda elementów skończonych. Metoda ta łączy metodę sztywnych elementów skończonych z klasyczną metodą elementów skończonych. W wyniku takiego podejścia otrzymuje się diagonalną macierz mas. W artykule przedstawiono wyniki symulacji numerycznych dotyczące drgań własnych płyt zbiorczych oraz wpływ liczby elementów, na które dzielono płyty, na drgania układu strzepującego.
Źródło:
Archive of Mechanical Engineering; 2011, LVIII, 1; 27-47
0004-0738
Pojawia się w:
Archive of Mechanical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nonlinear double-beam system dynamics
Dynamika nieliniowego układu belki podwójnej
Autorzy:
Koziol, Piotr
Pilecki, Rafał
Powiązania:
https://bibliotekanauki.pl/articles/1852508.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
belka podwójna
dynamika nieliniowa
rozwiązanie pół-analityczne
metoda hybrydowa
inżynieria kolejowa
double-beam
nonlinear dynamics
semi-analytical solution
hybrid method
railway engineering
Opis:
Double-beam model is considered in many investigations both theoretical and typically engineering ones. One can find different studies concerning analysis of such structures behaviour, especially in the cases where the system is subjected to dynamic excitations. This kind of model is successfully considered as a reliable representation of railway track. Inclusion of nonlinear physical and geometrical properties of rail track components has been justified by various computational studies and theoretical analyses. In order to properly describe behaviour of real structures their nonlinear properties cannot be omitted. Therefore a necessity to search appropriate analytical nonlinear models is recognized and highlighted in published literature. This paper presents essential extension of previously carried out double-beam system analysis. Two nonlinear factors are taken into account and parametrical analysis of the semi-analytical solution is undertaken with special emphasis on different range of parameters describing nonlinear stiffness of foundation and layer between beams. This study is extended by preliminary discussion regarding the dynamic effects produced by a series of loads moving along the upper beam. A new solution for the case of several forces acting on the upper beam with different frequencies of their variations in time is presented and briefly discussed.
Model belki podwójnej jest często wykorzystywany w budowie układów wielowarstwowych opisujących zjawiska związane z ruchomymi obciążeniami. Nieliniowe i stochastyczne właściwości tych układów wpływają znacząco na ich dynamiczne zachowania, co zostało potwierdzone zarówno eksperymentalnie, jak i w wyniku badań teoretycznych. Dlatego wskazana jest szczegółowa analiza czułości rozważanych modeli na różne parametry, przed ich zastosowaniem do badania rzeczywistych konstrukcji. W artykule rozważany jest problem odpowiedzi układu belki podwójnej na system sił poruszających się wzdłuż górnej belki ze stałą prędkością i różnymi częstotliwościami, przy założeniu różnych wartości parametrów opisujących nieliniową sztywność dwóch warstw: podłoża i warstwy łączącej belki. Otrzymane semi-analityczne rozwiązanie dla opisanego przypadku jest znaczącym rozszerzeniem poprzednio opublikowanych rezultatów. Założenie dotyczące występowania dwóch nieliniowości prowadzi do konieczności zastosowania szeregu analitycznych aproksymacji, włączając dekompozycję Adomiana i falkową estymację szukanego rozwiązania. Te nakładające się przybliżenia czynią całą procedurę bardziej skomplikowaną i dlatego kontrolowanie zbieżności rozwiązań jest trudniejsze niż w przypadku poprzednio rozważanych uproszczonych modeli. Analiza parametryczna, wykonana dla szerokiego zakresu różnych parametrów, pokazuje, że nieliniowość warstwy pomiędzy belkami wpływa bardziej znacząco na zachowanie układu, w porównaniu do podobnego założenia dotyczącego podłoża. Analiza przedstawiona w artykule może być traktowana jako kolejny etap określenia zakresu stosowalności modelu i zbadania możliwości jego zastosowania w inżynierii kolejowej, w odniesieniu do dwuwarstwowego modelu toru kolejowego, opartego na układzie belki podwójnej, w którym pierwsza warstwa opisuje szyny, a druga modeluje warstwę podkładów. Takie podejście do modelowania drogi szynowej zostało już wcześniej poddane walidacji razem z hybrydową semi-analityczną metodą rozwiązania opartą o aproksymacje wykorzystujące filtry falkowe typu „coiflet”. Rozszerzenie tego modelu o wprowadzenie dodatkowej nieliniowości, stanowi ważny element badań w zakresie analizy dynamiki dróg szynowych.
Źródło:
Archives of Civil Engineering; 2021, 67, 2; 337-353
1230-2945
Pojawia się w:
Archives of Civil Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Kidney Segmentation in CT Data Using Hybrid Level-Set Method with Ellipsoidal Shape Constraints
Autorzy:
Skalski, A.
Heryan, K.
Jakubowski, J.
Drewniak, T.
Powiązania:
https://bibliotekanauki.pl/articles/221728.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Level Set method
kidney
CT data
image segmentation
ellipsoid
Opis:
With development of medical diagnostic and imaging techniques the sparing surgeries are facilitated. Renal cancer is one of examples. In order to minimize the amount of healthy kidney removed during the treatment procedure, it is essential to design a system that provides three-dimensional visualization prior to the surgery. The information about location of crucial structures (e.g. kidney, renal ureter and arteries) and their mutual spatial arrangement should be delivered to the operator. The introduction of such a system meets both the requirements and expectations of oncological surgeons. In this paper, we present one of the most important steps towards building such a system: a new approach to kidney segmentation from Computed Tomography data. The segmentation is based on the Active Contour Method using the Level Set (LS) framework. During the segmentation process the energy functional describing an image is the subject to minimize. The functional proposed in this paper consists of four terms. In contrast to the original approach containing solely the region and boundary terms, the ellipsoidal shape constraint was also introduced. This additional limitation imposed on evolution of the function prevents from leakage to undesired regions. The proposed methodology was tested on 10 Computed Tomography scans from patients diagnosed with renal cancer. The database contained the results of studies performed in several medical centers and on different devices. The average effectiveness of the proposed solution regarding the Dice Coefficient and average Hausdorff distance was equal to 0.862 and 2.37 mm, respectively. Both the qualitative and quantitative evaluations confirm effectiveness of the proposed solution.
Źródło:
Metrology and Measurement Systems; 2017, 24, 1; 101-112
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Cellular particle swarm optimization with a simple adaptive local search strategy for the permutation flow shop scheduling problem
Autorzy:
Seck-Tuoh-Mora, Juan C.
Medina-Marin, Joselito
Martinez-Gomez, Erick S.
Hernandez-Gress, Eva S.
Hernandez-Romero, Norberto
Volpi-Leon, Valeria
Powiązania:
https://bibliotekanauki.pl/articles/230060.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
flow shop
particle swarm optimization (PSO)
local search strategy
hybrid search method
cellular automata
scheduling
Opis:
Permutation flow shop scheduling problem deals with the production planning of a number of jobs processed by a set of machines in the same order. Several metaheuristics have been proposed for minimizing the makespan of this problem. Taking as basis the previous Alternate Two-Phase PSO (ATPPSO) method and the neighborhood concepts of the Cellular PSO algorithm proposed for continuous problems, this paper proposes the improvement of ATPPSO with a simple adaptive local search strategy (called CAPSO-SALS) to enhance its performance. CAPSO-SALS keeps the simplicity of ATPPSO and boosts the local search based on a neighborhood for every solution. Neighbors are produced by interchanges or insertions of jobs which are selected by a linear roulette scheme depending of the makespan of the best personal positions. The performance of CAPSO-SALS is evaluated using the 12 different sets of Taillard’s benchmark problems and then is contrasted with the original and another previous enhancement of the ATPPSO algorithm. Finally, CAPSO-SALS is compared as well with other ten classic and state-of-art metaheuristics, obtaining satisfactory results.
Źródło:
Archives of Control Sciences; 2019, 29, 2; 205-226
1230-2384
Pojawia się w:
Archives of Control Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigations of CrN/TiO2 coatings obtained in a hybrid PVD/ALD method on Al-Si-Cu alloy substrate
Autorzy:
Staszuk, Marcin
Powiązania:
https://bibliotekanauki.pl/articles/2204527.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
ALD
PVD
hybrid coatings
TiO2
aluminum alloys
corrosion resistant
atomic layer deposition
physical vapor deposition
powłoki hybrydowe
stopy aluminium
osadzanie warstw atomowych
fizyczne osadzanie z fazy gazowej
odporność na korozję
Opis:
The paper addresses an important scientific topic from the utilitarian point of view concerning the surface treatment of Al-Si-Cu aluminum alloys by PVD/ALD hybrid coating deposition. The influence of the conditions of deposition of titanium oxide in CrN/TiO2 coatings on their structure and properties, in particular corrosion resistance, were investigated. The TiO2 layer was produced by the atomic layer deposition (ALD) method with a variable number of cycles. Structural investigations were performed using scanning and transmission electron microscopy (SEM and TEM), atomic force microscopy (AFM), and Raman spectroscopy methods. Electrochemical properties were analyzed using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. The CrN/TiO2 hybrid coating with titanium oxide deposited at 500 ALD cycles showed the best corrosion properties. It was also found that the prerequisite for obtaining the best electrochemical properties was the amorphous structure of titanium oxide in the tested hybrid coatings. The high tribological properties of the tested coatings were also confirmed.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2023, 71, 2; art. no. e144622
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of Tool Steel with Cr/CrN Type Hybrid Coatings, Obtained by PVD Method
Autorzy:
Kasprzycka, E.
Powiązania:
https://bibliotekanauki.pl/articles/356736.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
hybrid coating
PVD treatment
wear
corrosion
Opis:
The paper discusses the results of investigations of material, tribological and anti-corrosion properties of hybrid coatings of the Cr/CrN type, consisting of chromium and chromium nitride, formed on the surface of alloy tool steel by the Arc-PVD method. Investigations of the morphology and microstructure of hybrid coatings, as well as of their phase composition were carried out. The studies on mechanical properties included tests on hardness and Young’s modulus using the nanoindentation method. Tests on adhesion were conducted using the scratch-test method. Tribological properties of the obtained coatings were evaluated by the pin-on-disc method. Resistance to corrosion was determined by electrochemical methods. It was shown that hybrid coatings of the Cr/CrN type are characterized by good adhesion to the substrate and very good tribological properties, as well as by very good resistance to corrosion in a solution containing chlorine ions.
Źródło:
Archives of Metallurgy and Materials; 2019, 64, 1; 293-301
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hybrid maximum power point search method using temperature measurements in partial shading conditions
Autorzy:
Mroczka, J.
Ostrowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/221430.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
maximum power point
partial shading
perturb and observe
temperature measurement
Opis:
Photovoltaic panels have a non-linear current-voltage characteristics to produce the maximum power at only one point called the maximum power point. In the case of the uniform illumination a single solar panel shows only one maximum power, which is also the global maximum power point. In the case an irregularly illuminated photovoltaic panel many local maxima on the power-voltage curve can be observed and only one of them is the global maximum. The proposed algorithm detects whether a solar panel is in the uniform insolation conditions. Then an appropriate strategy of tracking the maximum power point is taken using a decision algorithm. The proposed method is simulated in the environment created by the authors, which allows to stimulate photovoltaic panels in real conditions of lighting, temperature and shading.
Źródło:
Metrology and Measurement Systems; 2014, 21, 4; 733-740
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Green supplier selection in edible oil production by a hybrid model using Delphi method and Green Data Envelopment Analysis (GDEA)
Autorzy:
Banaeian, N.
Nielsen, I. E.
Mobli, H.
Omid, M.
Powiązania:
https://bibliotekanauki.pl/articles/406770.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
GDEA
delphi method
green supplier selection
edible oil
carbon footprint
Opis:
An organization’s environmental performance is affected by its suppliers’ environmental performance, and selecting green suppliers is a strategic decision in order to be more competitive in today’s global market. By developing green movement across the globe, organizations are under pressure to reduce the emissions across their supply chain. Formerly the food production systems was oriented and optimized to satisfy economic demands and the nutritional needs of a rapidly growing world population. The food production industry requires large inputs of resources and causes several negative environmental effects. In recent years, environment factors rapidly emerging as an important issue for decision makers in food industries. This study identifies best supplier in holistic perspective for edible oil production, and proposes a hybrid model using Delphi method and Green Data Envelopment Analysis (GDEA). Delphi method identifies the main criteria influenced in supplier selection process based on opinion of company purchase experts. GDEA evaluates the overall performances of suppliers and choose green supplier. Proposed hybrid model applied to a well-known company who produce edible oil (palm, soybean and olive oil) to evaluate green suppliers (among 13 main potential suppliers). Delphi questionnaire included 17 factors which were from financial, services, qualitative and environmental factors. The factors with the highest Delphi score (raw material price, quality, delivery and carbon footprint) entered in DEA model and high efficiency suppliers selected. Results showed that the most efficient raw oil suppliers of company are: S4 among soybean oil suppliers, P1 among palm oil suppliers and O3 among olive oil suppliers. Also palm oil not only has fewer price and carbon footprint but also the highest mean efficiency.
Źródło:
Management and Production Engineering Review; 2014, 5, 4; 3-8
2080-8208
2082-1344
Pojawia się w:
Management and Production Engineering Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of Acoustic Emission Signals and Damage Analysis During the Tensile Test on Al8011 Hybrid Composites by Stir Casting Method
Autorzy:
Kannan, C. R.
Suresh, S.
Navaneetha Krishnan, M.
Powiązania:
https://bibliotekanauki.pl/articles/2203742.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Al8011
stir casting
acoustic emission
tensile
corrosion
Opis:
Metal network compounds have primary properties. The use of lightweight and low vitality is a testament to the growing interest in the automotive industry. Aluminum alloys, due to their advanced physical, mechanical and tribological properties, have become a highly emerging material for a variety of industrial applications and the importance of efficient material selection is explained. In this paper, an Al8011 hybrid metal matrix composite is developed through the stir casting process. The different weight proportions of B4C (3%, 6%, 9% & 12%) and fixed proportions of 2% MoS2 have been used. Composite developed are subjected to mechanical properties evaluation and seawater corrosion studies following standard procedures. To study the porosity of the composite samples, theoretical density and actual density are calculated. An acoustic emission system-assisted tensile test is carried out to report the strength of the composite. From this experimental method, adding reinforcement can increase the tensile strength and hardness of the composites. Under sea water, the increase in reinforcement found an increase in corrosion resistance. Fractured surfaces were perused using SEM and EDS analysis.
Źródło:
Archives of Metallurgy and Materials; 2023, 68, 1; 223--235
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design of Hybrid Precoder for mm-Wave MIMO System Based on Generalized Triangular Decomposition Method
Autorzy:
Thurpati, Sammaiah
Muthuchidambaranathan, P.
Powiązania:
https://bibliotekanauki.pl/articles/2124753.pdf
Data publikacji:
2022
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
millimeter-wave
mmWave
SVD
GTD
hybrid precoding
massive MIMO
Opis:
Hybrid precoding techniques are lately involved a lot of interest for millimeter-wave (mmWave) massive MIMO systems is due to the cost and power consumption advantages they provide. However, existing hybrid precoding based on the singular value decomposition (SVD) necessitates a difficult bit allocation to fit the varying signal-to-noise ratios (SNRs) of altered sub-channels. In this paper, we propose a generalized triangular decomposition (GTD)-based hybrid precoding to avoid the complicated bit allocation. The development of analog and digital precoders is the reason for the high level of design complexity in analog precoder architecture, which is based on the OMP algorithm, is very non-convex, and so has a high level of complexity. As a result, we suggest using the GTD method to construct hybrid precoding for mmWave mMIMO systems. Simulated studies as various system configurations are used to examine the proposed design. In addition, the archived findings are compared to a hybrid precoding approach in the classic OMP algorithm. The proposed Matrix Decomposition’s simulation results of signal-to-noise ratio vs spectral efficiencies.
Źródło:
International Journal of Electronics and Telecommunications; 2022, 68, 3; 519--525
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Noise Elimination of a Multi-tone Broadband Noise with Hybrid Helmholtz Mufflers Using a Simulated Annealing Method
Autorzy:
Chiu, M-C.
Powiązania:
https://bibliotekanauki.pl/articles/176674.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
multiple tones
hybrid
Helmholtz
four-pole transfer matrix method
SA method
Opis:
Noise control is essential in an enclosed machine room where the noise level has to comply with the occupational safety and health act. In order to overcome a pure tone noise with a high peak value that is harmful to human hearing, a traditional reactive muffler has been used. However, the traditional method for designing a reactive muffler has proven to be time-consuming and insufficient. In order to efficiently reduce the peak noise level, interest in shape optimization of a Helmholtz muffler is coming to the forefront. Helmholtz mufflers that deal with a pure tone have been adequately researched. However, the shape optimization of multi-chamber Helmholtz mufflers that deal with a broadband noise hybridized with multiple tones within a constrained space has been mostly ignored. Therefore, this study analyzes the sound transmission loss (STL) and the best optimized design for a hybrid Helmholtz muffler under a space- constrained situation. On the basis of the plane wave theory, the four-pole system matrix used to evaluate the acoustic performance of a multi-tone hybrid Helmholtz muffler is presented. Two numerical cases for eliminating one/two tone noises emitted from a machine room using six kinds of mufflers (muffler AF) is also introduced. To find the best acoustical performance of a space-constrained muffler, a numerical assessment using a simulated annealing (SA) method is adopted. Before the SA operation can be carried out, the accuracy of the mathematical model has been checked using the experimental data. Eliminating a broadband noise hybridized with a pure tone (130 Hz) in Case I reveals that muffler C composed of a one- chamber Helmholtz Resonator and a one-chamber dissipative element has a noise reduction of 54.9 (dB). Moreover, as indicated in Case II, muffler F, a two-chamber Helmholtz Resonator and a one-chamber dissipative element, has a noise reduction of 69.7 (dB). Obviously, the peak values of the pure tones in Case I and Case II are efficiently reduced after the muffler is added. Consequently, a successful approach in eliminating a broadband noise hybridized with multiple tones using optimally shaped hybrid Helmholtz mufflers and a simulated annealing method within a constrained space is demonstrated.
Źródło:
Archives of Acoustics; 2012, 37, 4; 489-498
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
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