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Wyszukujesz frazę "L. J." wg kryterium: Autor


Tytuł:
Remarks on Statistical Design Centering
Autorzy:
Opalski, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/226467.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
statistical design centering
design yield
realistic worst-case design
stochastic approximation
propagation of variance
Monte Carlo simulation
Opis:
The paper overviews optimization based statistical design centering techniques for analog circuits. Emphasis is placed on dependence between formulation of quality indices, problem formulation, and computational complexity of design centering algorithms, executed in single- or multiple-processor environments. For characterization of solution techniques a standard CMOS op-amp design case and a simplified computational complexity analysis are used.
Źródło:
International Journal of Electronics and Telecommunications; 2011, 57, 2; 159-167
2300-1933
Pojawia się w:
International Journal of Electronics and Telecommunications
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Serpent
Autorzy:
Marciniak, K.
Kern, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/702603.pdf
Data publikacji:
2005
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
CARMEN FIGURATUM
LATIN
POETRY
Opis:
A Latin translation of the famous 'carmen figuratum' by the Polish Ogden Nash.
Źródło:
Meander; 2005, 60, 2; 278
0025-6285
Pojawia się w:
Meander
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical study on in-cylinder blending by means of a simultaneous direct injection of two liquid fuels in a heavy duty compression ignition engine
Autorzy:
Kapusta, Ł. J.
Teodorczyk, A.
Powiązania:
https://bibliotekanauki.pl/articles/175277.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dual fuel
injection
n-hexane
heavy duty engine
Opis:
Dual fuel combustion has been recently of high interest, mainly in terms of utilization of fuels different than diesel fuel in compression ignition engines. Depending on the properties of a fuel which is additional to diesel fuel, and the type of the additional fuel supply method the combustion process may be strongly modified comparing to single fuel combustion. Nowadays the modification of the combustion process becomes the reason for implementing the dual fuelling process. However, still the main reason for its implementation remains the utilization of nonconventional fuels in compression ignition engines. Among different types of dual fuel systems the one based on simultaneous direct injection of two fuels seems to be most flexible one. It allows to stratify the charge in the cylinder, blend two different fuels at any ratio and does not decrease volumetric efficiency. Therefore, this study aims at mixture formation in a heavy duty engine employing simultaneous direct injection of two different liquid fuels. Special attention was paid to spray breakup and simultaneous evaporation of two fuels which are the key processes in mixture formation.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2015, 128; 5-18
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
HRTF Adjustments with Audio Quality Assessments
Autorzy:
Yao, S. N.
Chen, L. J.
Powiązania:
https://bibliotekanauki.pl/articles/950215.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
HRTF
PEAQ
cone of confusion
headphones
surround
Opis:
There are an increasing number of binaural systems embedded with head-related transfer functions (HRTFs), so listeners can experience virtual environments via conventional stereo loudspeakers or head- phones. As HRTFs vary from person to person, it is difficult to select appropriated HRTFs from already existing databases for users. Once the HRTFs in a binaural audio device hardly match the real ones of the users, poor localization happens especially on the cone of confusion. The most accurate way to obtain personalized HRTFs might be doing practical measurements. It is, however, expensive and time consuming. Modifying non-individualized HRTFs may be an effort-saving way, though the modifications are always accompanied by undesired audio distortion. This paper proposes a flexible HRTF adjustment system for users to define their own HRTFs. Also, the system can keep sounds from suffering intolerable distortion based on an objective measurement tool for evaluating the quality of processed audio.
Źródło:
Archives of Acoustics; 2013, 38, 1; 55-62
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Artificial bee colony based state feedback position controller for PMSM servo-drive – the efficiency analysis
Autorzy:
Tarczewski, T.
Niewiara, L. J.
Grzesiak, L. M.
Powiązania:
https://bibliotekanauki.pl/articles/200239.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
tuning
PMSM servo-drive
artificial bee colony algorithm
linear-quadratic optimization problem
pole placement
Opis:
This paper presents a state feedback controller (SFC) for position control of PMSM servo-drive. Firstly, a short review of the commonly used swarm-based optimization algorithms for tuning of SFC is presented. Then designing process of current control loop as well as of SFC with feedforward path is depicted. Next, coefficients of controller are tuned by using an artificial bee colony (ABC) optimization algorithm. Three of the most commonly applied tuning methods (i.e. linear-quadratic optimization, pole placement technique and direct selection of coefficients) are used and investigated in terms of positioning performance, disturbance compensation and robustness against plant parameter changes. Simulation analysis is supported by experimental tests conducted on laboratory stand with modern PMSM servo-drive.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 5; 997-1007
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Application of extended Kalman filter for estimation of periodic disturbance and velocity ripple reduction in PMSM drive
Autorzy:
Niewiara, Ł. J.
Tarczewski, T.
Grzesiak, L M.
Powiązania:
https://bibliotekanauki.pl/articles/201499.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
extended Kalman filter
disturbance estimation
PMSM drive
pulsating torque
velocity ripple reduction
Opis:
In this paper an application of extended Kalman filter (EKF) for estimation and attenuation of periodic disturbance in permanent magnet synchronous motor (PMSM) drive is investigated. Most types of disturbances present into PMSM drive were discussed and described. The mathematical model of the plant is presented. Detailed information about the design process of the disturbance estimator was introduced. A state feedback controller (SFC) with feedforward realizes the regulation and disturbance compensation. The theoretical analysis was supported by experimental tests on the laboratory stand. Both time- and frequency-domain analysis of the estimation results and angular velocity were performed. A significant reduction of velocity ripple has been achieved.
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2020, 68, 5; 983-995
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Automatic Synthesis of Musical Phrases from Multi-Pitch Samples
Autorzy:
Pluta, M.
Spalek, L. J.
Delekta, R. J.
Powiązania:
https://bibliotekanauki.pl/articles/177577.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound synthesis
synthesis methods
sampling
Concatenative Sound Synthesis
Opis:
Sound synthesizers are a natural element of a musician’s toolset. In music arrangement, samplers can often produce satisfactory results, but it requires a combination of manual and automatic methods that may be arduous at times. Concatenative Sound Synthesis reproduces many of natural performance- and expression-related nuances but at a cost of high demand for processing power. Here, another method of musical phrase synthesis aimed at music arrangement is presented that addresses these and other related issues. Contrary to common practice, we propose to record and utilize sound samples containing not one, but short sequences of pitches. In effect, natural pitch transitions are preserved and phrases appear to be much smoother, despite using very limited set of performance rules. The proof-of-concept implementation of the proposed method is discussed in detail along with attempts at optimizing the final sound effects, based on auditory tests. The limitations and future applications of the synthesizer are also discussed.
Źródło:
Archives of Acoustics; 2017, 42, 2; 235-247
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-performance PMSM servo-drive with constrained state feedback position controller
Autorzy:
Tarczewski, T.
Skiwski, M.
Niewiara, L. J.
Grzesiak, L. M.
Powiązania:
https://bibliotekanauki.pl/articles/200374.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
constrained control
model predictive approach
permanent magnet synchronous motor
position control
state feedback control
model predykcyjny
silnik synchroniczny z magnesem trwałym
sprzężenie zwrotne
Opis:
This paper describes high-performance permanent magnet synchronous motor (PMSM) servo-drive with constrained state feedback (SFC) position controller. Superior behavior of the control system has been achieved by applying SFC with constraints handling method based on a posteriori model predictive approach (MPAC). The concept utilizes predictive equations obtained from discrete-time model of the PMSM to compute control signals which generate admissible values of the future state variables. The novelty of the proposed solution lies in the limitation of several state-space variables in servo-drive control system. Since MPAC has firstly been applied to limit more than one state-space variable of the plant, necessary conditions for introducing constraints into multivariable control system with SFC are depicted. Due to the low complexity of proposed algorithm, a low cost microprocessor, STM32F4, is employed to execute the state feedback position control with model predictive approach to constraints handling. Experimental results show that the proposed control method provides superior performance of PMSM servodrive with modern SiC based voltage source inverter (VSI).
Źródło:
Bulletin of the Polish Academy of Sciences. Technical Sciences; 2018, 66, 1; 49-58
0239-7528
Pojawia się w:
Bulletin of the Polish Academy of Sciences. Technical Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Increased AST/ALT ratio in azotaemic dogs infected with Babesia canis
Autorzy:
Zygner, W.
Gojska-Zygner, O.
Norbury, L.J.
Wedrychowicz, H.
Powiązania:
https://bibliotekanauki.pl/articles/31893.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
dog
animal disease
infection
Babesia canis
azotemia
canine babesiosis
babesiosis
kidney injury
protozoan parasite
Opis:
The AST/ALT ratio was estimated in 182 dogs infected with Babesia canis. Among these dogs 65 had anaemia and 68 were azotaemic. Student’s t test was used to compare means of the AST/ALT ratio in anaemic and non-anaemic dogs, and in azotaemic and non-azotaemic dogs (p < 0.05). The differences in AST/ALT ratio between anaemic (1.52 ± 1.15) and non-anaemic (1.76 ± 1.34) dogs were statistically insignificant (p = 0.23), however, the comparison of AST/ALT ratio between azotaemic (2.68 ± 1.52) and non-azotaemic (1.08 ± 0.53) dogs revealed a significantly higher value of this index in azotaemic dogs (p = 0.00). The present results suggest that kidney injury contributed to increased AST activity in these dogs.
Źródło:
Polish Journal of Veterinary Sciences; 2012, 15, 3
1505-1773
Pojawia się w:
Polish Journal of Veterinary Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Characterization of Phyllosticta hostae causing Phyllosticta leaf spot on spider lily in China
Autorzy:
Yi, R.H.
Gan, L.J.
Chen, J.
Xu, X.L.
Powiązania:
https://bibliotekanauki.pl/articles/66837.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Phyllosticta hostae
leaf spot
plant disease
spider lily
Hymenocallis littoralis
tropical plant
herb
China
Opis:
Leaf spot disease on the spider lily [Hymenocallis littoralis (Jacq.) Salisb.] continues to cause serious problems in China. To confirm the pathogen, the pathogenicity of isolates from diseased leaves was tested according to Koch’s postulates. The isolates were tentatively identified using morphological characteristics and confirmation was done by phylogenetic analysis of the translation elongation factor 1-alpha gene (TEF1), the actin gene (ACT), and internal transcibed spacer (ITS) sequences using neighbor-joining (NJ), maximum parsimony (MP), and Bayesian inference (BI) methods. The pathogen was identified as Phyllosticta hostae. Molecular analysis indicated very little diversity in the TEF1, ACT, and ITS gene. This is the first report of P. hostae causing leaf spot disease on spider lily in China.
Źródło:
Journal of Plant Protection Research; 2015, 55, 4
1427-4345
Pojawia się w:
Journal of Plant Protection Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Studies into new, environmentally friendly Ag-Cu-Zn-Sn brazing alloys of low silver content
Badania nowych, ekologicznych spoiw twardych Ag-Cu-Zn-Sn o niskiej zawartości srebra
Autorzy:
Wierzbicki, L. J.
Malec, W.
Stobrawa, J.
Cwolek, B.
Juszczyk, B.
Powiązania:
https://bibliotekanauki.pl/articles/354086.pdf
Data publikacji:
2011
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kadm
srebro
spoiwa ekologiczne
stopy lutownicze
właściwości mechaniczne
mikrostruktura
skład fazowy
cadmium
silver
environmentally friendly alloys
brazing alloys
mechanical properties
microstructure
phase composition
Opis:
The paper present selected results of the research conducted for elimination of toxic cadmium from silver based brazing alloys of Ag-Cu-Zn-Cd type. The investigations were conducted with nine new alloys of constant, low silver content (25%) and diversified copper (38.8-46%), zinc (19-32%) and tin (3-10%) contents. Tin was selected as potentially the best cadmium substitute basing on literature review and analysis of equilibrium systems. For examinations and tests a series of ingots in laboratory scale was manufactured, as well as some ingots in pilot scale for the selected, most promising alloys. Complex metallographic examinations of the brazing alloys samples produced in various conditions were made as well as analyses of their phase composition. Also mechanical properties of the samples both in ambient and in elevated temperatures were examined, and physical and technological properties and usability of the alloys were determined. The last stage of the study covered laboratory trials of brazing using the selected alloys. Basing on the results it can be said that there is a possibility to substitute selected cadmium containing silver-based alloys with environmentally friendly alloys of Ag-Cu-Zn-Sn type of relatively low silver content. Low range of melting point was reached, as preliminary assumed. Mechanical properties of the studied alloys strongly depend on temperature, and present limited plasticity in room temperature, while at high temperature (over 500°C) present superplasticity. The examined alloys show good spreadability and the brazing tests confirmed their good reactions both with copper and brass base in a wide temperature range.
W niniejszym artykule przedstawiono wybrane wyniki prac, których celem jest wyeliminowanie toksycznego kadmu ze srebrowych spoiw twardych typu Ag-Cu-Zn-Cd. Badaniami objęto 9 nowych gatunków stopów o stałej, niskiej zawartości srebra (25%) oraz zróżnicowanej zawartości miedzi (38,8-46%), cynku (19-32%) oraz cyny (3-10%). Cyna została wytypowana, na podstawie analizy literaturowej oraz układów równowagowych, jako potencjalnie najlepszy zamiennik kadmu. Wytworzono szereg wlewków w skali laboratoryjnej oraz dla wybranych, najbardziej obiecujących gatunków spoiw, wlewki w skali półtechnicznej przeznaczone do badań i prób. Przeprowadzono kompleksowe badania metalograficzne próbek spoiw wytworzonych w róznych warunkach oraz dokonano analizy skżadu fazowego. Wykonano także badania wżaściwości mechanicznych próbek zarówno w temperaturze otoczenia jak i podwyższonej oraz badania właściwości fizycznych, technologicznych i użytkowych. W ostatnim etapie pracy przeprowadzono laboratoryjne próby lutowanie przy zastosowaniu wybranych spoiw. Uzyskane wyniki badań pozwalają stwierdzić, że możliwe jest zastąpienie wybranych gatunków spoiw srebrowych kadmowych stopami ekologicznymi z grupy Ag-Cu-Zn-Sn o stosunkowo niskiej zawartości srebra. Uzyskano, zakładany we wstępnym etapie prac, niski zakres temperatury topnienia. Właściwości mechaniczne badanych stopów silnie zależą od temperatury, charakteryzują się one ograniczoną plastycznościa w temperaturze pokojowej, by w wysokiej temperaturze (ponad 500°C) wykazywać cechy nadplastyczne. Badane spoiwa charakteryzują się dobrą rozpływnością, a próby lutowania wykazały, że dobrze reagują zarówno z podłożem miedzianym jak i mosiężnych w szerokim zakresie temperatury.
Źródło:
Archives of Metallurgy and Materials; 2011, 56, 1; 147-158
1733-3490
Pojawia się w:
Archives of Metallurgy and Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Numerical Assessment of a One-Mass Spring-Based Electromagnetic Energy Harvester on a Vibrating Object
Autorzy:
Chiu, M.-C.
Chang, Y.-C.
Yeh, L.-J.
Chung, C.-H.
Powiązania:
https://bibliotekanauki.pl/articles/177720.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
spring
harvester
generator
permanent magnet
simulated annealing
optimization
buckling
Fatigue
Opis:
The paper is an exploration of the optimal design parameters of a space-constrained electromagnetic vibration-based generator. An electromagnetic energy harvester is composed of a coiled polyoxymethylen circular shell, a cylindrical NdFeB magnet, and a pair of helical springs. The magnet is vertically confined between the helical springs that serve as a vibrator. The electrical power connected to the coil is actuated when the energy harvester is vibrated by an external force causing the vibrator to periodically move through the coil. The primary factors of the electrical power generated from the energy harvester include a magnet, a spring, a coil, an excited frequency, an excited amplitude, and a design space. In order to obtain maximal electrical power during the excitation period, it is necessary to set the system’s natural frequency equal to the external forcing frequency. There are ten design factors of the energy harvester including the magnet diameter (Dm), the magnet height (Hm), the system damping ratio (ζsys), the spring diameter (Ds), the diameter of the spring wire (ds), the spring length (ℓs), the pitch of the spring (ps), the spring’s number of revolutions (Ns), the coil diameter (Dc), the diameter of the coil wire (dc), and the coil’s number of revolutions (Nc). Because of the mutual effects of the above factors, searching for the appropriate design parameters within a constrained space is complicated. Concerning their geometric allocation, the above ten design parameters are reduced to four (Dm, Hm, ζsys, and Nc). In order to search for optimal electrical power, the objective function of the electrical power is maximized by adjusting the four design parameters (Dm, Hm, ζsys, and Nc) via the simulated annealing method. Consequently, the optimal design parameters of Dm, Hm, ζsys, and Nc that produce maximum electrical power for an electromagnetic energy harvester are found.
Źródło:
Archives of Acoustics; 2016, 41, 1; 119-131
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Acoustic absorption of a new class of alumina foams with various high-porosity levels
Autorzy:
Zieliński, T. G.
Potoczek, M.
Śliwa, R. E.
Nowak, Ł. J.
Powiązania:
https://bibliotekanauki.pl/articles/177924.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
sound absorption
porous materials
alumina foam
Opis:
Recently, a new class of ceramic foams with porosity levels up to 90% has been developed as a result of the association of the gelcasting process and aeration of the ceramic suspension. This paper presents and discusses original results advertising sound absorbing capabilities of such foams. The authors man- ufactured three types of alumina foams in order to investigate three porosity levels, namely: 72, 88, and 90%. The microstructure of foams was examined and typical dimensions and average sizes of cells (pores) and cell-linking windows were found for each porosity case. Then, the acoustic absorption coefficient was measured in a wide frequency range for several samples of various thickness cut out from the foams. The results were discussed and compared with the acoustic absorption of typical polyurethane foams proving that the alumina foams with high porosity of 88-90% have excellent sound absorbing properties competitive with the quality of sound absorbing PU foams of higher porosity.
Źródło:
Archives of Acoustics; 2013, 38, 4; 495-502
0137-5075
Pojawia się w:
Archives of Acoustics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Automatic Laser Interferometer And Vision Measurement System For Stripe Rod Calibration
Autorzy:
Zhao, M.
Huang, Q.-H.
Zhu, L.-J.
Qiu, Z.-M.
Powiązania:
https://bibliotekanauki.pl/articles/221047.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
stripe edge
automatic control
laser interferometer
vision measurement
Opis:
In order to calibrate the stripe precision of a leveling rod, an automatic laser interferometer and a vision measurement system were designed by Xi’an University of Technology in China. The rod was driven by a closed-loop control and the data were collected at the stop state to ensure precision. The laser interferometer provided not only the long distance data but also a position feedback signal in the automatic control loop. CCD camera and a vision measurement method were used to inspect the stripe edge position and defect. Apixel-equivalent self-calibration method was designed to improve precision. ROI (regions of interest) method and an outline tracing method were designed to quickly extract multiple stripe edges. A combination of the image data with the interferometer data reduces control difficulty and ensures the measurement accuracy. The vision measurement method reached sub-pixel precision and the defective edges were reported. The system can automatically calibrate a stripe leveling rod with a high degree of efficiency and precision.
Źródło:
Metrology and Measurement Systems; 2015, 22, 4; 491-502
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł

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