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Wyszukujesz frazę "reduction" wg kryterium: Temat


Tytuł:
3D Multi-Domain MFS Analysis of Sound Pressure Level Reduction Between Connected Enclosures
Autorzy:
Godinho, L.
Branco, F. G.
Mendes P., A.
Powiązania:
https://bibliotekanauki.pl/articles/177013.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Method of Fundamental Solutions (MFS)
domain decomposition
closed spaces
sound pressure level reduction
Opis:
In this paper, the authors study the 3D propagation of sound waves between two closed spaces. The separation element between the two rooms is considered to include either a small opening or a homogeneous lightweight panel, coupling the two spaces. A numerical study of this configuration is performed, trying to understand the influence of the position and geometry of this opening in the sound pressure level reduction curve at low and midfrequencies. Additionally, the coupling effect between the two acoustic spaces is analyzed, in order to better understand its importance when determining the sound pressure level reduction. Different boundary conditions are ascribed to the walls of these rooms, simulating both the completely reflecting and partially absorbing surfaces. The numerical modelling was performed using a multi-domain formulation of the Method of Fundamental Solutions (MFS). The system is composed of two coupled rooms, limited by rigid or by absorbing walls, and separated by a thin wall (tending to null thickness) with a small opening. An experimental validation of the proposed model is presented, comparing its results with those found experimentally for a reduced-scale model. It is important to note that, for such a configuration, a traditional single-domain approach using methods like the MFS or the BEM would lead to undetermined equation systems, and thus the proposed model makes use of a domain decomposition technique.
Źródło:
Archives of Acoustics; 2011, 36, 3; 575-601
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
3E - A new paradigm for the development of civil aviation
Autorzy:
Orkisz, Marek
Kuźniar, Michał
Powiązania:
https://bibliotekanauki.pl/articles/2097457.pdf
Data publikacji:
2020
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
airplane
electric propulsion
hybrid propulsion
distributed propulsion
reduction of emission exhaust
reduction of noise
decrease of fuel consumption
samolot
napęd elektryczny
napęd hybrydowy
napęd rozproszony
redukcja emisji spalin
redukcja hałasu
zmniejszenie zużycia paliwa
Opis:
Nowadays, in civil aviation, issues related to improving efficiency, reducing the costs of air operations as well as the negative impact of air transport on the environment are of increasing importance. These ideas allow the formulation of the paradigm relating to the development of air transport - ‘more Efficiently, more Economically, more Eco-friendly - 3E’. The article presents in a cross-sectional and synthetic way research conducted by leading scientific centres around the world as well as prototype aviation constructions designed by companies from the aviation industry. Benefits and disadvantages of future propulsions, such as purely electric, hybrid and distributed propulsions, were presented. Conclusions were formulated regarding further possible directions of civil aviation development, taking into account the improvement of its efficiency as well as economic and ecological indicators.
Źródło:
Combustion Engines; 2020, 59, 2; 3--10
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A comparative study for outlier detection methods in high dimensional text data
Autorzy:
Park, Cheong Hee
Powiązania:
https://bibliotekanauki.pl/articles/2201316.pdf
Data publikacji:
2023
Wydawca:
Społeczna Akademia Nauk w Łodzi. Polskie Towarzystwo Sieci Neuronowych
Tematy:
curse of dimensionality
dimension reduction
high dimensional text data
outlier detection
Opis:
Outlier detection aims to find a data sample that is significantly different from other data samples. Various outlier detection methods have been proposed and have been shown to be able to detect anomalies in many practical problems. However, in high dimensional data, conventional outlier detection methods often behave unexpectedly due to a phenomenon called the curse of dimensionality. In this paper, we compare and analyze outlier detection performance in various experimental settings, focusing on text data with dimensions typically in the tens of thousands. Experimental setups were simulated to compare the performance of outlier detection methods in unsupervised versus semisupervised mode and uni-modal versus multi-modal data distributions. The performance of outlier detection methods based on dimension reduction is compared, and a discussion on using k-NN distance in high dimensional data is also provided. Analysis through experimental comparison in various environments can provide insights into the application of outlier detection methods in high dimensional data.
Źródło:
Journal of Artificial Intelligence and Soft Computing Research; 2023, 13, 1; 5--17
2083-2567
2449-6499
Pojawia się w:
Journal of Artificial Intelligence and Soft Computing Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Comparative Study of Single- and Dual-Threshold Voltage SRAM Cells
Autorzy:
Kushwaha, P.
Chaudhry, A.
Powiązania:
https://bibliotekanauki.pl/articles/308384.pdf
Data publikacji:
2011
Wydawca:
Instytut Łączności - Państwowy Instytut Badawczy
Tematy:
5T SRAM
65 nm CMOS technology
6T SRAM
7T SRAM
low power SRAM
power reduction technique
Opis:
In this paper, a comparison has been drawn between 5 transistor (5T), 6T and 7T SRAM cells. All the cells have been designed using both single-threshold (conventional) and dual-threshold (dual-Vt) voltage techniques. Their respective delays and power consumption have been calculated at 180 nm and 65 nm CMOS technology. With technology scaling, power consumption decreases by 80% to 90%, with some increase in write time because of the utilization of high- Vt transistors in write critical path. The results show that the read delay of 7T SRAM cell is 9% lesser than 5T SRAM cell and 29% lesser than 6T SRAM cell due to the lower resistance of the read access delay path. While read power of 5T SRAM cell is reduced by 10% and 24% as compared to 7T SRAM, 6T SRAM cell respectively. The write speed, however, is degraded by 1% to 3% with the 7T and 5T SRAM cells as compared to the 6T SRAM cells due to the utilization of single ended architecture. While write power of 5T SRAM cell is reduced by up to 40% and 67% as compared to 7T SRAM, 6T SRAM cell respectively.
Źródło:
Journal of Telecommunications and Information Technology; 2011, 4; 124-130
1509-4553
1899-8852
Pojawia się w:
Journal of Telecommunications and Information Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A complexity efficient PAPR reduction scheme for FBMC-based VLC systems
Autorzy:
Roshdy, Radwa A.
Hussein, Aziza I.
Mabrook, Mohamed M.
Salem, Mohammed A.
Powiązania:
https://bibliotekanauki.pl/articles/2204164.pdf
Data publikacji:
2023
Wydawca:
Polska Akademia Nauk. Stowarzyszenie Elektryków Polskich
Tematy:
visible light communication
filter bank multicarrier
peak-to-average power ratio reduction
computational complexity
cube satellite communication link
inter-satellite communications
Opis:
Visible light communication based on a filter bank multicarrier holds enormous promise for optical wireless communication systems, due to its high-speed and unlicensed spectrum. Moreover, visible light communication techniques greatly impact communication links for small satellites like cube satellites, and pico/nano satellites, in addition to inter-satellite communications between different satellite types in different orbits. However, the transmitted visible signal via the filter bank multicarrier has a high amount of peak-to-average power ratio, which results in severe distortion for a light emitting diode output. In this work, a scheme for enhancing the peak-to-average power ratio reduction amount is proposed. First, an algorithm based on generating two candidates signals with different peak-to- average power ratio is suggested. The signal with the lowest ratio is selected and transmitted. Second, an alternate direct current-biased approach, which is referred to as the addition reversed method, is put forth to transform transmitted signal bipolar values into actual unipolar ones. The performance is assessed through a cumulative distribution function of peak-to-average power ratio, bit error rate, power spectral density, and computational complexity. The simulation results show that, compared to other schemes in literature, the proposed scheme attains a great peak-to-average power ratio reduction and improves the bit the error rate performance with minimum complexity overhead. The proposed approach achieved about 5 dB reduction amount compared to companding technique, 5.5 dB compared to discrete cosine transform precoding, and 8 dB compared to conventional direct current bias of an optical filter bank multicarrier. Thus, the proposed scheme reduces the complexity overhead by 15.7% and 55.55% over discrete cosine transform and companding techniques, respectively.
Źródło:
Opto-Electronics Review; 2023, 31, 1; art. no. e144919
1230-3402
Pojawia się w:
Opto-Electronics Review
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A conceptual design and numerical analysis of the mixerless urea-SCR system
Autorzy:
Kaźmierski, Bartosz
Górka, Krzysztof
Kapusta, Łukasz Jan
Powiązania:
https://bibliotekanauki.pl/articles/2097591.pdf
Data publikacji:
2021
Wydawca:
Polskie Towarzystwo Naukowe Silników Spalinowych
Tematy:
NOx
SCR
selective catalytic reduction
wall film
CFD
selektywna redukcja katalityczna
Opis:
In the present study, an innovative design of a urea-selective catalytic reduction (SCR) system without conventional mixing elements was developed. The aim was to obtain a high degree of urea decomposition, and uniform ammonia distribution at the inlet to the catalyst, while minimising the liquid film deposition and keeping the compact design. The concept of the design was based on creating high turbulence and elongating the flow paths of the droplets. The design was verified through a series of numerical simulations based on the Reynolds-averaged Navier-Stokes (RANS) approach and a discrete droplet model (DDM) spray representation. The analysis included various operating conditions as well as subcooled and superheated sprays. A uniform ammonia distribution was achieved regardless of the operating points and spray properties. Additionally, in the case of a flash-boiling injection, a further reduction of the wall film was observed.
Źródło:
Combustion Engines; 2021, 60, 4; 12--20
2300-9896
2658-1442
Pojawia się w:
Combustion Engines
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A contemporary multi-objective feature selection model for depression detection using a hybrid pBGSK optimization algorithm
Autorzy:
Kavi Priya, Santhosam
Pon Karthika, Kasirajan
Powiązania:
https://bibliotekanauki.pl/articles/2201021.pdf
Data publikacji:
2023
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
depression detection
text classification
dimensionality reduction
hybrid feature selection
wykrywanie depresji
klasyfikacja tekstu
redukcja wymiarowości
wybór funkcji
Opis:
Depression is one of the primary causes of global mental illnesses and an underlying reason for suicide. The user generated text content available in social media forums offers an opportunity to build automatic and reliable depression detection models. The core objective of this work is to select an optimal set of features that may help in classifying depressive contents posted on social media. To this end, a novel multi-objective feature selection technique (EFS-pBGSK) and machine learning algorithms are employed to train the proposed model. The novel feature selection technique incorporates a binary gaining-sharing knowledge-based optimization algorithm with population reduction (pBGSK) to obtain the optimized features from the original feature space. The extensive feature selector (EFS) is used to filter out the excessive features based on their ranking. Two text depression datasets collected from Twitter and Reddit forums are used for the evaluation of the proposed feature selection model. The experimentation is carried out using naive Bayes (NB) and support vector machine (SVM) classifiers for five different feature subset sizes (10, 50, 100, 300 and 500). The experimental outcome indicates that the proposed model can achieve superior performance scores. The top results are obtained using the SVM classifier for the SDD dataset with 0.962 accuracy, 0.929 F1 score, 0.0809 log-loss and 0.0717 mean absolute error (MAE). As a result, the optimal combination of features selected by the proposed hybrid model significantly improves the performance of the depression detection system.
Źródło:
International Journal of Applied Mathematics and Computer Science; 2023, 33, 1; 117--131
1641-876X
2083-8492
Pojawia się w:
International Journal of Applied Mathematics and Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Galerkin approximation method including space dimensional reduction - applied for solution of a heat conduction equation
Autorzy:
Nakonieczny, K.
Powiązania:
https://bibliotekanauki.pl/articles/118009.pdf
Data publikacji:
2012
Wydawca:
Polskie Towarzystwo Promocji Wiedzy
Tematy:
Galerkin approximation
dimensional reduction
heat conduction
Opis:
A multivariate data fitting procedure, based on the Galerkin minimization method, is studied in this paper. The main idea of the developed approach consists in projecting the set of data points from the original, higher-dimensional space, onto a line section. Then, the approximation problem is solved in the resulting one-dimensional space. The elaborated recipe can be designed so that it is computationally more efficient than the schemes based on the least squares minimization. The performance of the method is studied by comparison with the least squares and the moving least squares procedures in a number of examples, including the solution of the heat diffusion equation.
Źródło:
Applied Computer Science; 2012, 8, 2; 48-58
1895-3735
Pojawia się w:
Applied Computer Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Hardware-Efficient Structure of Complex Numbers Divider
Autorzy:
Cariow, A.
Cariowa, G.
Powiązania:
https://bibliotekanauki.pl/articles/114589.pdf
Data publikacji:
2017
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
complex-number divider
hardware complexity reduction
VLSI implementation
Opis:
In this correspondence an efficient approach to structure of hardware accelerator for calculating the quotient of two complex-numbers with reduced number of underlying binary multipliers is presented. The fully parallel implementation of a complex-number division using the conventional approach to structure organization requires 4 multipliers, 3 adders, 2 squarers and 2 divider while the proposed structure requires only 3 multipliers, 6 adders, 2 squarers and 2 divider. Because the hardware complexity of a binary multiplier grows quadratically with operand size, and the hardware complexity of an binary adder increases linearly with operand size, then the complex-number divider structure containing as little as possible embedded multipliers is preferable.
Źródło:
Measurement Automation Monitoring; 2017, 63, 6; 212-213
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A hybrid approach to dimension reduction in classification
Autorzy:
Krawczak, M.
Szkatuła, G.
Powiązania:
https://bibliotekanauki.pl/articles/206425.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
data series
dimension reduction
envelopes
essential attributes
heteroassociation
machine learning from examples
decision rules
classification
Opis:
In this paper we introduce a hybrid approach to data series classification. The approach is based on the concept of aggregated upper and lower envelopes, and the principal components here called 'essential attributes', generated by multilayer neural networks. The essential attributes are represented by outputs of hidden layer neurons. Next, the real valued essential attributes are nominalized and symbolic data series representation is obtained. The symbolic representation is used to generate decision rules in the IF. . . THEN. . . form for data series classification. The approach reduces the dimension of data series. The efficiency of the approach was verified by considering numerical examples.
Źródło:
Control and Cybernetics; 2011, 40, 2; 527-551
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of reducing switch count in three-level NPC inverter – analysis in steady states
Autorzy:
Beniak, R.
Rogowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193464.pdf
Data publikacji:
2017
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reduction of switch count
three-level NPC inverter
space vector modulation
Opis:
The proof of a concept for a new method of modulation has been presented which reduce switch count in a three-level neutral point clamped (3L-NPC) inverter. The method is an implementation of space vector modulation (SVM) by means of a prediction algorithm and sequences of transistors, which are not common in use. Those sequences make active use of clamping diodes of the inverter. The prediction algorithm analyzes possible sequences of transistors’ states and choose those which offers smaller switch count. Measurements of steady states were taken on prototype 3L-NPC.
Źródło:
Power Electronics and Drives; 2017, 2, 37/2; 117-126
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of reducing switching losses in three-level NPC inverter
Autorzy:
Beniak, R.
Rogowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/1193262.pdf
Data publikacji:
2016
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
reduction of switching losses
three-level NPC inverter
space vector modulation
Opis:
The aim of the paper is to present a concept of implementation of a space vector modulation (SVM) algorithm, which is used to create alternating current waveforms of changing amplitude and frequency in power inverters. The main goal of the method is to decrease the number of state changes in power transistors. It is realized by utilizing a prediction algorithm and sequences of transistors, which are not common in use. The method requires measurement of inverter output current flow. The prediction algorithm analyzes possible sequences of transistors’ states and choose those which offers smaller switch count. A decrease of about 20% was obtained for the cases tested. This paper presents simulation result for selected driving scenario. The described method decreases the number of state changes in power transistors and therefore it is a potentially good method to considerably decrease energy losses of multilevel inverter-powered drive.
Źródło:
Power Electronics and Drives; 2016, 1, 36/2; 55-63
2451-0262
2543-4292
Pojawia się w:
Power Electronics and Drives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A molecular dynamics study of the influence of chemical reduction on the structure of amorphous Germania
Autorzy:
Witkowska, A.
Murawski, L.
Bergmański, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963001.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
oxide glasses
hydrogen reduction
molecular dynamics
structural modelling
Opis:
The contribution is dedicated to the molecular dynamics (MD) study of the structure of reduced germania glass of composition 1Ge 1GeO2. The work is inspired by a recent report on the formation of Ge clusters in hydrogen reduced germanate glasses containing oxides of heavy metals. The MD simulations have been performed in the microcanonical (NVE) ensemble, using a simple two-body Born-Mayer-Huggins interaction potential. A tendency of germanium atoms to agglomeration into clusters, observed in the present calculations, is compared with an analogous tendency of Bi and Pb atoms, observed previously in the xBi (1-x)GeO2 and xPb (1-x)GeO2 systems. The differences in the short and medium-range order in GeO2 system between the 1Ge 1GeO2 and GeO2 glasses are discussed.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 2; 273-281
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A New Approach of an Error Detecting and Correcting Circuit by Arithmetic Logic Blocks
Autorzy:
Kavitha, S.
Hashim, Fazida Hanim
Kamal, Noorfazila
Powiązania:
https://bibliotekanauki.pl/articles/226549.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
EDAC
ALU
speed
block reduction
power
slew rate
Opis:
This paper proposes a unique method of an error detection and correction (EDAC) circuit, carried out using arithmetic logic blocks. The modified logic blocks circuit and its auxiliary components are designed with Boolean and block reduction technique, which reduced one logic gate per block. The reduced logic circuits were simulated and designed using MATLAB Simulink, DSCH 2 CAD, and Microwind CAD tools. The modified, 2:1 multiplexer, demultiplexer, comparator, 1-bit adder, ALU, and error correction and detection circuit were simulated using MATLAB and Microwind. The EDAC circuit operates at a speed of 454.676 MHz and a slew rate of -2.00 which indicates excellence in high speed and low-area.
Źródło:
International Journal of Electronics and Telecommunications; 2019, 65, 2; 313-318
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new low SNR underwater acoustic signal classification method based on intrinsic modal features maintaining dimensionality reduction
Autorzy:
Ju, Yang
Wei, Zhengxian
Li, Huangfu
Feng, Xiao
Powiązania:
https://bibliotekanauki.pl/articles/259300.pdf
Data publikacji:
2020
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
acoustic
low SNR
signal classification
feature maintain
dimension reduction
Opis:
The classification of low signal-to-noise ratio (SNR) underwater acoustic signals in complex acoustic environments and increasingly small target radiation noise is a hot research topic. . This paper proposes a new method for signal processing—low SNR underwater acoustic signal classification method (LSUASC)—based on intrinsic modal features maintaining dimensionality reduction. Using the LSUASC method, the underwater acoustic signal was first transformed with the Hilbert-Huang Transform (HHT) and the intrinsic mode was extracted. the intrinsic mode was then transformed into a corresponding Mel-frequency cepstrum coefficient (MFCC) to form a multidimensional feature vector of the low SNR acoustic signal. Next, a semi-supervised fuzzy rough Laplacian Eigenmap (SSFRLE) method was proposed to perform manifold dimension reduction (local sparse and discrete features of underwater acoustic signals can be maintained in the dimension reduction process) and principal component analysis (PCA) was adopted in the proces of dimension reduction to define the reduced dimension adaptively. Finally, Fuzzy C-Means (FCMs), which are able to classify data with weak features was adopted to cluster the signal features after dimensionality reduction. The experimental results presented here show that the LSUASC method is able to classify low SNR underwater acoustic signals with high accuracy.
Źródło:
Polish Maritime Research; 2020, 2; 187-198
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł

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