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Abstrakt

The main goal of this paper is to analyze the matching function in the Polish labour market in 1994‒2008. Matching function is the relationship between outflows from unemployment to employment and the number of unemployed persons and vacancies as well as other variables which affect the efficiency of the matching process directly or indirectly. Such matching function in its augmented form is estimated here for Poland with the use of data from register of unemployed persons.

The results indicate that there is a statistically stronger impact of the unemployed than vacancies on new hires. Furthermore, the institutional conditions of the labour market, the structure of the unemployed and the participants of active labour market programs (ALMP) play a role in the matching process.

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Autorzy i Afiliacje

Sylwia Roszkowska

Abstrakt

At the Kielce University of Technology a new concept of accurate measurements of sphericity deviations of machine parts has been developed. The concept is based upon measurement of roundness profiles in many clearly defined cross-sections of the workpiece. Measurements are performed with the use of typical radial measuring instrument equipped with a unit allowing accurate positioning of the ball. The developed concept required finding a solution to numerous problems relating to the principle of the radial measurement. One of the problems to be solved was matching of measured roundness profiles. The paper presents an outline of the developed concept of sphericity measurement, a mathematical model of profile matching and results of the verification of the model.

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Autorzy i Afiliacje

Krzysztof Stępień
Dariusz Janecki
Stanisław Adamczak

Abstrakt

Keypoint detection is a basic step in many computer vision algorithms aimed at recognition of objects, automatic navigation and analysis of biomedical images. Successful implementation of higher level image analysis tasks, however, is conditioned by reliable detection of characteristic image local regions termed keypoints. A large number of keypoint detection algorithms has been proposed and verified. In this paper we discuss the most important keypoint detection algorithms. The main part of this work is devoted to description of a keypoint detection algorithm we propose that incorporates depth information computed from stereovision cameras or other depth sensing devices. It is shown that filtering out keypoints that are context dependent, e.g. located at boundaries of objects can improve the matching performance of the keypoints which is the basis for object recognition tasks. This improvement is shown quantitatively by comparing the proposed algorithm to the widely accepted SIFT keypoint detector algorithm. Our study is motivated by a development of a system aimed at aiding the visually impaired in space perception and object identification.
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Autorzy i Afiliacje

Paweł Strumiłło
Karol Matusiak
Piotr Skulimowski

Abstrakt

This paper presents a novel complementary CPWfed slotted microstrip patch antenna for operation at 2.4 GHz, 5.2 GHz and 6.3 GHz frequencies. The primary structure consists of the complementary split ring resonator slots on a patch and the design is fabricated on FR-4 epoxy substrate with substrate thickness of 1.6 mm. The described structure lacks the presence of a ground plane and makes use of a number of circular complementary SRRs along with rectangular slots on the radiating patch. The structure provides a wide bandwidth of around 390 MHz, 470 MHz and 600 MHz at the three bands with return losses of -11.5 dB, -24.3996dB and -24.4226 dB, respectively. The inclusion of the rectangular slots in the CSRR based slot antenna with stairecase structure improved the performance with respect to return loss.

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Autorzy i Afiliacje

Kaustubh Bhattacharyya
Rupanda Thangjam
Sivaranjan Goswami
Kumaresh Sarmah
Sunandan Baruah

Abstrakt

One major problem in the design of ultrasonic transducers results from a huge impedance mismatch between piezoelectric ceramics and the loading medium (e.g. gaseous, liquid, and biological media). Solving this problem requires the use of a matching layer (or layers). Optimal selection of materials functioning as matching layers for piezoelectric transducers used in transmitting and receiving ultrasound waves strictly depends on the type of the medium receiving the ultrasound energy. Several methods allow optimal selection of materials used as matching layers. When using a single matching layer, its impedance can be calculated on the basis of the Chebyshev, DeSilets or Souquet criteria. In the general case, the typically applied methods use an analogy to a transmission line in order to calculate the transmission coefficient T. This paper presents an extension of transmission coefficient calculations with additional regard to the attenuation coefficients of particular layers. The transmission coefficient T is optimised on the basis of a genetic algorithm method. The obtained results indicate a significant divergence between the classical calculation methods and the genetic algorithm method.

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Autorzy i Afiliacje

Tadeusz Gudra
Dariusz Banasiak

Abstrakt

Using intelligent materials and sensors to monitor the safety of concrete structures is a hot topic in the field of civil engineering. In order to realize the omni-directional monitoring of concrete structural damage, the authors of this paper designed and fabricated an embedded annular piezoelectric ultrasonic sensor using the annular piezoelectric lead zirconate titanate (PZT) ceramic as a sensing element and epoxy resin as the matching and the backing layers. The influence of different matching and backing layers thickness on the acoustic characteristic parameters of the sensor were studied. The results show that the resonant frequency corresponding to the axial mode of annular piezoelectric ceramics moves toward the high frequency direction with the decrease of the height of piezoelectric ceramics, and the radial vibration mode increases as well as the impedance peak. With the thickness of the backing layer increases from 1 mm to 2 mm, the radial resolution of the annular piezoelectric ultrasonic sensor is enhanced, the pulse width is reduced by 39% comparing with the sensors which backing layer is 1 mm, and the head wave amplitude and −3 dB bandwidth are increased by 61% and 66%, respectively. When the matching layer thickness is 3 mm, the sensor has the highest amplitude response of 269 mV and higher sensitivity.
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Autorzy i Afiliacje

Haoran Li
1
Yan Hu
2
Laibo Li
1
Dongyu Xu
2 3

  1. Shandong Provincial Key Lab of Preparation and Measurement of Building Materials, University of Jinan, Jinan 250022, PR China
  2. School of Civil Engineering, Central South University, Changsha 410075, PR China
  3. School of Civil Engineering and Architecture, Linyi University, Linyi 276000, PR China

Abstrakt

The δ18O data for the last 8000 years in the Greenland NGRIP1, GRIP, DYE-3 and GISP2 ice cores have been analyzed stratigraphically in search of potentially meaningful boundaries and units. Pattern matching of the profiles is supported by using graphical display enhancements, calculating spectral trend curves and generating a compound profile. Techniques routinely used in subsurface geology have been applied in correlating the profiles. Four major stratigraphic units are identified (8.1–4.9, 4.9–3.3, 3.3–1.9 and 1.9–0.1 ka b2k), resulting in an improved understanding of the climate change after the Holocene Climate Optimum. Correlatable higher-order boundaries are identified within these units. The layers between the boundaries show δ18O patterns which generally are similar in character, the differences being ascribed to lateral variations in the factors that control the isotope content of the ice. The layering forms a series of short-lived low-amplitude aperiodic oscillations on a centennial time scale. The suggestion is that these higher-order boundaries and δ18O oscillations have climatic significance. Equivalent units are tentatively identified in ice-core data from the Agassiz and Renland ice caps. Comparison with other climate proxies or stratigraphies from the Northern Hemisphere is expected to render support for the here proposed scheme. It will then serve to guide and constrain the analysis of the dynamics of the climatic fluctuations for the study period.

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Autorzy i Afiliacje

Matheus G.G. De Jong
Arie C. Seijmonsbergen
Leo W.S. De Graaff

Abstrakt

W ostatnich latach, integracja zbiorów danych punktów reprezentujących powierzchnie tego samego terenu za pomocą techniki dopasowania (matching techniques jest jednym z głównych kierunków badań. Ogromne zasoby danych mogą być otrzymane różnymi technologami. Zastosowanie momentów jako cechy wysokiego poziomu w celu dopasowania powierzchni jest rozwiązaniem globalnym, które pozwala na znalezienie parametrów transformacji pomiędzy tymi układami bez wstępnych warunków. Dokładność i szybkość wyznaczanych parametrów transformacji zależą od dokładności i szybkości wyznaczanych momentów. Niniejsza praca przedstawia efektywną metodę obliczenia momentów bezwładności sieci TIN i DEM dla dopasowania powierzchni. Metoda ta opiera się o twierdzenie Greena, które pozwala na przekształcenie momentów bezwładności obliczonych z podwójnej całki na całkę liniową wyznaczaną wzdłuż trzech boków trójkątów w TIN i w DEM. Zastosowana metoda daje możliwość 4-krotnego zmniejszenia liczby operacji mnożenia. Wyprowadzone wzory umożliwiające obliczenie momentów w oparciu o twierdzenie Greena mają prostą postać. Pozwala to na efektywne wykonanie obliczeń na komputerze. Przy zastosowaniu zaproponowanej metody dokładność obliczonych momentów będzie zachowana, bo proces obliczenia jest bezpośredni i nie wymaga stosowania aproksymacji.
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Autorzy i Afiliacje

Chinh Ke Luong

Abstrakt

Matched sampling is a methodology used to estimate treatment effects. A caliper mechanism is used to achieve better similarity among matched pairs. We investigate finite sample properties of matching with caliper and propose a slight modification to the existing mechanism. The simulation study compare performance of both methods and show that standard caliper perform well only in case of constant treatment or uniform propensity score distribution. Secondly, in a case of non-uniform distribution and non-uniform treatment the dynamic caliper method outperform standard caliper matching.

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Autorzy i Afiliacje

Paweł Strawiński

Abstrakt

In this work, an approach to the design of broadband thickness-mode piezoelectric transducer is pre- sented. In this approach, simulation of discrete time model of the impulse response of matched and backed piezoelectric transducer is used to design high sensitivity, broad bandwidth, and short-duration impulse response transducers. The effect of matching the performance of transmitting and receiving air backed PZT-5A transducer working into water load is studied. The optimum acoustical characteristics of the quarter wavelength matching layers are determined by a compromise between sensitivity and pulse duration. The thickness of bonding layers is smaller than that of the quarter wavelength matching layers so that they do not change the resonance peak significantly. Our calculations show that the −3 dB air backed transducer bandwidth can be improved considerably by using quarter wavelength matching layers. The computer model developed in this work to predict the behavior of multilayer structures driven by a transient waveform agrees well with measured results. Furthermore, the advantage of this this model over other approaches is that the time signal for optimum set of matching layers can be predicted rapidly
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Autorzy i Afiliacje

Mohamed G.S. Ali
Nour Z. Elsayed
Ebtsam A. Eid

Abstrakt

Cardiac Radiofrequency (RF) ablation is a commonly used clinical procedure for treating many cardiac arrhythmias. However, the efficacy of RF ablation may be limited by two factors: small ventricular lesions and impedance rise, leading to coagulum formation and desiccation of tissue. In this paper, a high frequency (HF) energy ablation system operating at 27.12 MHz based on an automated load matching system was developed. A HF energy matched probe associated to the automated impedance matching device ensures optimal transfer of the energy to the load. The aim of this study was to evaluate this energy for catheter ablation of the atrioventricular junction.

In vivo studies were performed using 10 sheep to characterize the lesions created with the impedance matching system. No cardiac perforation was noted. No thrombus was observed at the catheter tip. Acute lesions ranged from 3 to 45 mm in diameter (mean ±SD = 10.3±10) and from 1 to 15 mm in depth (6.7±3.9), exhibiting a close relationship between HF delivered power level and lesion size. Catheter ablation using HF current is feasible and appears effective in producing a stable AV block when applied at the AV junction and large myocardial lesions at ventricular sites.

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Autorzy i Afiliacje

Rouane Amar
Bru Paul

Abstrakt

This paper proposes a microfounded model featuring frictional labor markets that generates procyclical R&D expenditures as a result of optimizing behavior by heterogeneous monopolistically competitive firms. This allows to show that business cycle fluctuations affect the aggregate endogenous growth rate of the economy. Consequently, transitory shocks leave lasting level effects. This mechanism is responsible for economically significant hysteresis effects that significantly increase the welfare cost of business cycles relative to the exogenous growth model. I show that this has serious policy implications and creates ample space for policy intervention. I find that several static and countercyclical subsidy schemes are welfare improving. Importantly, I find that due to labor market frictions subsidizing incumbent firms generates large and positive welfare effects.
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Autorzy i Afiliacje

Marcin Bielecki
1

  1. University of Warsaw, Poland, Narodowy Bank Polski

Abstrakt

Radiation of sound waves from a semi-infinite cylindrical duct with perforated end whose outer wall is coated with acoustically absorbent material is investigated by using the Wiener-Hopf technique in conjunction with the mode matching technique. A semi-infinite duct with a perforated screen can be used as a model for many engineering applications, such as noise reduction in exhausts of automobile engines, in modern aircraft jet, and turbofan engines. In particular, we aim to find the effects of outer lining and perforated end to sound pressure level for the underlying problem by using the standard Wiener-Hopf and mode matching techniques. We also present some numerical illustrations by determining the sound pressure level for different parameters such as soft and rigid outer surface, with and without perforated end, etc. Such investigations are useful in the reduction of noise effects generated through variety of sources.

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Autorzy i Afiliacje

Burhan Tiryakioglu

Abstrakt

Template matching is a process to identify and localize a template image on an original image. Several methods are commonly used for template matching, one of which uses the Fourier transform. This study proposes a modification of the method by adding an improved rotation to the Fourier transform. Improved rotation in this study uses increment rotation and three shear methods for the template image rotation process. The three shear rotation method has the advantage of precise and noisefree rotation results, making the template matching process even more accurate. Based on the experimental results, the use of 10°angle increments has increased template matching accuracy. In addition, the use of three shear rotations can improve the accuracy of template matching by 13% without prolonging the processing time.
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Autorzy i Afiliacje

Marvin Chandra Wijaya
1

  1. Computer Engineering Departement, Maranatha Christian University, Bandung, Indonesia

Abstrakt

This paper deals with designing and simulation of an efficient RF-DC energy harvesting system for a remote control device. GSM down-link frequency of 935MHz to 960MHz and uplink frequency of 890MHz to 915MHz is taken as the RF source with centre frequency as 950MHz and 900MHz respectively. The simulation model has been created by using Advanced Design System (ADS) software. Performance of the circuit has been tested with matching and without matching circuits. The output voltage obtained was 0.372V DC and maximum efficiency up to 35.73% was achieved for the downlink GSM frequency by the lumped method for -10dB input source power. By considering more number of rectifier stages, output DC voltage can be increased and it can be utilized for replacing DC battery of the remote control device.
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Autorzy i Afiliacje

Deepak Kumar Nayak
1
Arjuna Muduli
2

  1. ECE, Budge Budge Institute of Technology, Kolkata, West Bengal, India
  2. ECE, Koneru Lakshmaiah Education Foundation, Vaddeswaram, Andhra Pradesh, India

Abstrakt

The copy-move forgery detection (CMFD) begins with the preprocessing until the image is ready to process. Then, the image features are extracted using a feature-transform-based extraction called the scale-invariant feature transform (SIFT). The last step is features matching using Generalized 2 Nearest- Neighbor (G2NN) method with threshold values variation. The problem is what is the optimal threshold value and number of keypoints so that copy-move detection has the highest accuracy. The optimal threshold value and number of keypoints had determined so that the detection has the highest accuracy. The research was carried out on images without noise and with Gaussian noise.

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Autorzy i Afiliacje

R. Rizal Isnanto
Ajub Ajulian Zahra
Imam Santoso
Muhammad Salman Lubis

Abstrakt

The method of evaluating the resonant frequencies of multilayered resonator containing demagnetized ferrites is presented. The detailed solution of Maxwell's equations for such a structure by means of the radial modes matching method for TE0mn modes is given. The results of calculations using developed and launched computer program are given. Results of calculations are compared with those obtained by other method using CST simulator. These results are in close agreement, which proves the correctness of the method. The developed solution, and the software program can be used to measure the initial permeability of ferrites.
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Autorzy i Afiliacje

Krzysztof Derzakowski
1

  1. Institute of Radiolectronics and MultimediaTechnology, Warsaw University of Technology, Poland

Abstrakt

Istotny problem dopasowania dwóch powierzchni generowanych w postaci TIN lub DEM na podstawie zbiorów punktów przestrzennych, otrzymanych przy pomocy różnych sensorów w różnych układach, polega na wyznaczeniu parametrów transformacji pomiędzy nimi bez wspólnych punktów w obu układach. Dla rozwiązania tego problemu wykorzystane są elementy powierzchniowe w formie trójkątów (model TIN) albo kwadratów (DEM). Praca przedstawia propozycję analitycznego rozwiązania zadania .xlopasowania" (matching) dwóch powierzchni na podstawie wykorzystania momentów bezwładności sieci generowanych trójkątów (model TIN). Proces dopasowania dwóch powierzchni zostaje zrealizowany na zasadzie warunku minimalizacji ,.długości momentów" liczonych pomiędzy i-tym modelem TIN pierwszej powierzchni i j-lym modelem TIN drugiej powierzchni na trzech płaszczyznach OXY, OXZ, OYZ. Wten sposób parametry transformacji zostaną wyznaczane bez punktów wspólnych i zadanie transformacji drugiej powierzchni na pierwszą zostanie zrealizowane.
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Autorzy i Afiliacje

Chinh Ke Luong

Abstrakt

W ostatnich latach zgromadzony został ogromny zasób danych informatycznych o terenie w postaci zdjęć lotniczych, satelitarnych, SAR, IFSAR (lnSAR), LIDAR, DTM terenu itd., otrzymanych różnymi sposobami i przy użyciu różnych sensorów. Integracja danych jest jednym z głównych kierunków badań. Linie konturowe powierzchni terenu na zdjęciu należą do podstawowych cech, które są wykorzystywane w procesie dopasowania metodą FBM (Feature-Based Matching). Niniejsza praca przedstawia propozycję zastosowania niezmienników momentów linii konturowych, zwanych cechami wysokiego poziomu, do dopasowania powierzchni. Linie konturowe w pierwszym etapie muszą być rozpoznane i wydzielone. Dla realizacji tego celu zastosowano transformatę wavelets. Połączenie automatycznie wydzielanych za pomocą transformaty wavelets linii konturowych wraz z wyznaczanymi ich momentami w 2-D (na zdjęciu) lub w 3-D (przestrzenne linie) wykorzystywanymi w procesie dopasowania powierzchni umożliwia pełną automatyzację procesu wykonania wzajemnej i absolutnej orientacji pary zdjęć, jak również wykonanie orientacji wewnętrznej i zewnętrznej poszczególnych zdjęć.
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Autorzy i Afiliacje

Chinh Ke Luong

Abstrakt

The study aims at evaluating crop insurance effects on the farms’ production and investment indicators in Lithuania. The Common Agricultural Policy after 2020 considers measures helping farmers to adapt to climate change. For this reason, it is essential to evaluate existing risk management measures in order to propose appropriate schemes for the next programming period. In order to evaluate crop insurance effects on the farms’ production and investment indicators farm-level, data from Farm Accountancy Data Network dataset and propensity score matching approach was used. Study period was 2008–2017. The study revealed that participation in crop insurance schemes was influenced by the factors such as age of the farmer, wealth, specialization, and location of the farm. The study also demonstrated that crop insurance did not show statistically significant effects on the selected farms’ indicators. The main reason was support from the national and EU funds.
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Autorzy i Afiliacje

Virginia Namiotko
1
ORCID: ORCID
Aistė Galnaitytė
1
ORCID: ORCID
Irena Kriščiukaitienė
1
ORCID: ORCID
Ahmet Ali Koç
2
ORCID: ORCID

  1. Institute of Economics and Rural Development of the Lithuanian Centre for Social Sciences A. Vivulskio Str. 4A-13, LT-03220 Vilnius, Lithuania
  2. Akdeniz University, Faculty of Economics and Administrative Sciences, Department of Economics, Antalya, Turkey
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Abstrakt

Similarity assessment between 3D models is an important problem in many fields including medicine, biology and industry. As there is no direct method to compare 3D geometries, different model representations (shape signatures) are developed to enable shape description, indexing and clustering. Even though some of those descriptors proved to achieve high classification precision, their application is often limited. In this work, a different approach to similarity assessment of 3D CAD models was presented. Instead of focusing on one specific shape signature, 45 easy-to-extract shape signatures were considered simultaneously. The vector of those features constituted an input for 3 machine learning algorithms: the random forest classifier, the support vector classifier and the fully connected neural network. The usefulness of the proposed approach was evaluated with a dataset consisting of over 1600 CAD models belonging to 9 separate classes. Different values of hyperparameters, as well as neural network configurations, were considered. Retrieval accuracy exceeding 99% was achieved on the test dataset.

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Bibliografia

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Autorzy i Afiliacje

Dawid Machalica
1
Marek Matyjewski
2

  1. Warsaw Institute of Aviation, Warsaw, Poland.
  2. Warsaw University of Technology, Institute of Aeronautics and Applied Mechanics, Warsaw, Poland.

Abstrakt

As one of the key techniques in the fully mechanized mining process, equipment selection and matching has a great effect on security, production and efficiency. The selection and matching of fully mechanized mining equipment in thin coal seam are restricted by many factors. In fully mechanized mining (FMM) faced in thin coal seams (TCS), to counter the problems existing in equipment selection, such as many the parameters concerned and low automation, an expert system (ES) of equipment selection for fully mechanized mining longwall face was established. A database for the equipment selection and matching expert system in thin coal seam, fully mechanized mining face has been established. Meanwhile, a decision-making software matching the ES was developed. Based on several real world examples, the reliability and technical risks of the results from the ES was discussed. Compared with the field applications, the shearer selection from the ES is reliable. However, some small deviations existed in the hydraulic support and scraper conveyor selection. Then, the ES was further improved. As a result, equipment selection in fully mechanized mining longwall face called 4301 in the Liangshuijing coal mine was carried out by the improved ES. Equipment selection results of the interface in the improved ES is consistent with the design proposal of the 4301 FMM working face. The reliability of the improved ES can meet the requirements of the engineering. It promotes the intelligent and efficient mining of coal resources in China.

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Autorzy i Afiliacje

Chen Wang
ORCID: ORCID
Jie Chen
Cheng Liu
Chengyu Jiang
ORCID: ORCID
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Abstrakt

The core goal of this paper is to put forward a feasible scheme of noise reduction for a target forklift on the basis of solving the problem of vibration and acoustic radiation from complex structures in infinite domain. Based on the previous report and vibration acceleration tests, the acoustic virtual wind tunnel model of forklift power compartment was established using finite element method and boundary element method, in which the perfectly matched layer was first applied to simulate the attenuation propagation of sound waves in air. In addition, according to the distribution characteristics of sound pressure field with different frequencies, the acoustic energy mainly radiated through the bottom and right side, and concentrated in the low frequency. Consequently, the acoustic packaging design for the whole forklift power compartment was presented, and a satisfying noise reduction effect was achieved.
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Bibliografia

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Autorzy i Afiliacje

Enlai Zhang
1 2
Zhiqi Liu
2
Jingjing Zhang
3
Jiahe Lin
4

  1. School of Mechanical and Automotive Engineering, Xiamen University of Technology, Xiamen, China
  2. Chengyi University College, Jimei University, Xiamen, China
  3. College of Applied Science and Technology, Hainan University, Danzhou, China
  4. Department of Mechanical and Electrical Engineering, Xiamen University, Xiamen, China

Abstrakt

This paper presents the research studies carried out on the application of lattice Boltzmann method (LBM) to computational aeroacoustics (CAA). The Navier-Stokes equation-based solver faces the difficulty of computational efficiency when it has to satisfy the high-order of accuracy and spectral resolution. LBM shows its capabilities in direct and indirect noise computations with superior space-time resolution. The combination of LBM with turbulence models also work very well for practical engineering machinery noise. The hybrid LBM decouples the discretization of physical space from the discretization of moment space, resulting in flexible mesh and adjustable time-marching. Moreover, new solving strategies and acoustic models are developed to further promote the application of LBM to CAA.

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Autorzy i Afiliacje

Weidong Shao
Jun Li

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