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Wyświetlanie 1-6 z 6
Tytuł:
Rapid Design Optimization of Multi-Band Antennas by Means of Response Features
Autorzy:
Kozieł, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/221503.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
antenna design
antenna measurements
computer-aided design
surrogate modelling
feature-based optimization
Opis:
This work examines the reduced-cost design optimization of dual- and multi-band antennas. The primary challenge is independent yet simultaneous control of the antenna responses at two or more frequency bands. In order to handle this task, a feature-based optimization approach is adopted where the design objectives are formulated on the basis of the coordinates of so-called characteristic points (or response features) of the antenna response. Due to only slightly nonlinear dependence of the feature points on antenna geometry parameters, optimization can be attained at a low computational cost. Our approach is demonstrated using two antenna structures with the optimum designs obtained in just a few dozen of EM simulations of the respective structure.
Źródło:
Metrology and Measurement Systems; 2017, 24, 2; 337-346
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Anthropometric predispositions for swimming from the perspective of biomechanics
Autorzy:
Rejman, M.
Tyc, Ł.
Kociuba, M.
Bornikowska, A.
Rudnik, D.
Kozieł, S.
Powiązania:
https://bibliotekanauki.pl/articles/306959.pdf
Data publikacji:
2018
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
pływanie
profil antropometryczny
biomechanika
swimming
anthropometric profile
biomechanics
Opis:
Early identification of anthropological potential in swimmers is considered important to the recruitment and selection of children and adolescents to perform extensive and strenuous training. The aim of the research was a comparative analysis of the anthropometric parameters and indicators of adult, elite swimmers with people who had never trained for swimming. It was assumed that the specific characteristics of the swimmers’ somatic composition referred to the laws of swimming biomechanics. Methods: Anthropometric measurements were taken in a group of elite male swimmers (N = 28), aged 17–24. The same set of measurements was taken in a homogeneous control group of students of physical education. An anthropometric profile significantly differentiating swimmers from the control group was constructed. Next, a linear forward stepwise discriminant analysis was conducted to investigate which indices can be used to distinguish the two groups. Results: It seems significant that a specific somatic composition trait of swimmers in the form of a relatively long shank was observed, which had not been observed in earlier studies. Additionally, indices of relatively slim hand dimension, and indices describing a “reversed triangle” shape of trunk, were the most powerful discrimination variables between the two examined groups. Conclusion: The results obtained cannot be generalised to the entire population of swimmers, however referring them to the laws of biomechanics of swimming allows for the continuation of research into identifying the prognostic traits desirable for success among young swimmers.
Źródło:
Acta of Bioengineering and Biomechanics; 2018, 20, 4; 151-159
1509-409X
2450-6303
Pojawia się w:
Acta of Bioengineering and Biomechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Computationally Efficient Two-Objective Optimization of Compact Microwave Couplers through Corrected Domain Patching
Autorzy:
Kozieł, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/221065.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
computer-aided design
compact circuits
microwave couplers
multi-objective optimization
domain patching
surrogate modelling
response correction
Opis:
Finding an acceptable compromise between various objectives is a necessity in the design of contemporary microwave components and circuits. A primary reason is that most objectives are at least partially conflicting. For compact microwave structures, the design trade-offs are normally related to the circuit size and its electrical performance. In order to obtain comprehensive information about the best possible trade-offs, multi-objective optimization is necessary that leads to identifying a Pareto set. Here, a framework for fast multi-objective design of compact micro-strip couplers is discussed. We use a sequential domain patching (SDP) algorithm for numerically efficient handling of the structure bandwidth and the footprint area. Low cost of the process is ensured by executing SDP at the low-fidelity model level. Due to its bi-objective implementation, SDP cannot control the power split error of the coupler, the value of which may become unacceptably high along the initial Pareto set. Here, we propose a procedure for correction of the S-parameters’ characteristics of Pareto designs. The method exploits gradients of power split and bandwidth estimated using finite differentiation at the patch centres. The gradient data are used to correct the power split ratio while leaving the operational bandwidth of the structure at hand intact. The correction does not affect the computational cost of the design process because perturbations are pre-generated by SDP. The final Pareto set is obtained upon refining the corrected designs to the high-fidelity EM model level. The proposed technique is demonstrated using two compact microstrip rat-race couplers. Experimental validation is also provided.
Źródło:
Metrology and Measurement Systems; 2018, 25, 1; 139-157
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design Optimization and Trade-Offs of Miniaturized Wideband Antenna for Internet of Things Applications
Autorzy:
ul Haq, M. A.
Kozieł, S.
Powiązania:
https://bibliotekanauki.pl/articles/220987.pdf
Data publikacji:
2017
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
compact antennas
internet of things (IoT)
communication devices
numerical optimization
footprint-reduction-oriented design
Opis:
Internet of Things (IoT) will play an important role in modern communication systems. Thousands of devices will talk to each other at the same time. Clearly, smart and efficient hardware will play a vital role in the development of IoT. In this context, the importance of antennas increases due to them being essential parts of communication networks. For IoT applications, a small size with good matching and over a wide frequency range is preferred to ensure reduced size of communication devices. In this paper, we propose a structure and discuss design optimization of a wideband antenna for IoT applications. The antenna consists of a stepped-impedance feed line, a rectangular radiator and a ground plane. The objective is to minimize the antenna footprint by simultaneously adjusting all geometry parameters and to maintain the electrical characteristic of antenna at an acceptable level. The obtained design exhibits dimensions of only 3.7 mm × 11.8 mm and a footprint of 44 mm2, an omnidirectional radiation pattern, and an excellent pattern stability. The proposed antenna can be easily handled within compact communication devices. The simulation results are validated through measurements of the fabricated antenna prototype.
Źródło:
Metrology and Measurement Systems; 2017, 24, 3; 463-471
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Suppressing Side-Lobes of Linear Phased Array of Micro-Strip Antennas with Simulation-Based Optimization
Autorzy:
Kozieł, S.
Ogurtsov, S.
Bekasiewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/220985.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
linear antenna array
micro-strip antenna array
phased antenna array
antenna optimization
antenna array optimization
simulation-based optimization
surrogate model
Opis:
A simulation-based optimization approach to design of phase excitation tapers for linear phased antenna arrays is presented. The design optimization process is accelerated by means of Surrogate-Based Optimization (SBO); it uses a coarse-mesh surrogate of the array element for adjusting the array’s active reflection coefficient responses and a fast surrogate of the antenna array radiation pattern. The primary optimization objective is to minimize side-lobes in the principal plane of the radiation pattern while scanning the main beam. The optimization outcome is a set of element phase excitation tapers versus the scan angle. The design objectives are evaluated at the high fidelity level of description using simulations of the discrete electromagnetic model of the entire array so that the effects of element coupling and other possible interaction within the array structure are accounted for. At the same time, the optimization process is fast due to SBO. Performance and numerical cost of the approach are demonstrated by optimizing a 16-element linear array of microstrip antennas. Experimental verification has been carried out for a manufactured prototype of the optimized array. It demonstrates good agreement between the radiation patterns obtained from simulations and from physical measurements (the latter constructed through superposition of the measured element patterns).
Źródło:
Metrology and Measurement Systems; 2016, 23, 2; 193-203
0860-8229
Pojawia się w:
Metrology and Measurement Systems
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Komputerowa weryfikacja układów cyfrowyh CMOS utworzonych z podukładów zasilanych ze źródeł o różnych wartościach napięcia
Computer verification of a cmos digital circuit created by subcircuits supplied by different voltages
Autorzy:
Szcześniak, W.
Kozieł, S.
Jendernalik, W.
Hasse, L.
Szcześniak, P.
Powiązania:
https://bibliotekanauki.pl/articles/267925.pdf
Data publikacji:
2007
Wydawca:
Politechnika Gdańska. Wydział Elektrotechniki i Automatyki
Tematy:
redukcja poboru mocy
weryfikacja układu
układy CMOS
reduction in power consumption
verification system
CMOS settings
Opis:
W pracy zaprezentowano wyniki komputerowej weryfikacji cyfrowego układu CMOS utworzonego z klastrów Cn-1, Cn-2, …, Ci, … C0, z których każdy jest zasilany odpowiednio malejącymi wartościami napięć Vddn-1 > Vddn-2 > … > Vddi > … > Vdd0 . Zbiór klastrów {Ci} został utworzony przy pomocy algorytmu ECA (Evolutionary Clustering Algorithm) dla potrzeb redukcji mocy pobieranej ze źródła zasilającego. Otrzymane rozwiązanie charakteryzujące się zmniejszeniem zapotrzebowania na moc zasilającą nie powoduje pogorszenia przepustowości zaprojektowanego systemu cyfrowego CMOS.
The paper presents results of a computer simulation of a CMOS digital circuit composed of Cn-1, Cn-2, …, Ci, … C0 clusters. The clusters are supplied with voltages Vddn-1 > Vddn-2 > … > Vddi > … > Vdd0, respectively. Set of clusters {Ci} was created with aid of ECA (Evolutionary Clustering Algorithm) for reduction of power dissipated. The obtained result enables for power reduction without deteriorating the throughput of the designed CMOS circuit, measured as system latency.
Źródło:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej; 2007, 23; 105-108
1425-5766
2353-1290
Pojawia się w:
Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-6 z 6

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