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System Characterization (system + characterization)

Distribution by Scientific Domains
Engineering83%

Selected Abstracts

INTEGRATING DYNAMIC SYSTEMS MATERIALS INTO A MECHANICAL ENGINEERING CURRICULUM THROUGH INNOVATIVE USE OF WEB-BASED ACQUISITION AND HANDS-ON APPLICATION AND USE OF VIRTUAL GRAPHICAL USER INTERFACES Part 3: Dynamic Systems,Analytical and Experimental System Characterization

EXPERIMENTAL TECHNIQUES, Issue 1 2008
Pete Avitabile
First page of article [source]

Inverse Modeling Approach to Allogenic Karst System Characterization

GROUND WATER, Issue 3 2009
N. Dörfliger
Allogenic karst systems function in a particular way that is influenced by the type of water infiltrating through river water losses, by karstification processes, and by water quality. Management of this system requires a good knowledge of its structure and functioning, for which a new methodology based on an inverse modeling approach appears to be well suited. This approach requires both spring and river inflow discharge measurements and a continuous record of chemical parameters in the river and at the spring. The inverse model calculates unit hydrographs and the impulse responses of fluxes from rainfall hydraulic head at the spring or rainfall flux data, the purpose of which is hydrograph separation. Hydrograph reconstruction is done using rainfall and river inflow data as model input and enables definition at each time step of the ratio of each component. Using chemical data, representing event and pre-event water, as input, it is possible to determine the origin of spring water (either fast flow through the epikarstic zone or slow flow through the saturated zone). This study made it possible to improve a conceptual model of allogenic karst system functioning. The methodology is used to study the Bas-Agly and the Cent Font karst systems, two allogenic karst systems in Southern France. [source]

2D-Fractal Based Algorithms for Fine and Ultrafine Particulate Solids Systems Characterization

PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 4-5 2007
Giuseppe Bonifazi
Abstract Fractal geometry concerns the study of non-Euclidean geometrical figures generated by a recursive sequence of mathematical operations. The proposed 2D-fractal approach was applied to characterise the image structure and texture generated by fine and ultrafine particles when impacting on a flat surface. The work was developed with reference to particles usually produced in the ornamental stone sector during the different working phases carried out in dry conditions. Specific milling actions have been performed at a laboratoty scale on different ornamental stone products, in order to generate different particle populations to utilize in the study. The aim of the work was to develop a simple, reliable and low cost analytical set of procedures with the ability to establish correlations between particles detected by fractal characteristics and their classical attributes, e.g., i) size class distribution, ii) shape, iii) composition, etc. Such a logic should constitute the core of a control engine with the ability to optimize dust capture abatement strategies, according to produced dusts characteristics. [source]

Measurement accuracy enhancements for wideband modulated signals

INTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2003
A. A. Moulthrop
Abstract Time-domain waveform measurements of wideband modulated signals, although attractive for communication systems modeling applications, have until now lacked the required accuracy for quantitative analysis. New developments described here enhance the accuracy of these measurements, enabling their application to communication system characterization and modeling. © 2003 Wiley Periodicals, Inc. Int J RF and Microwave CAE 13: 32,39, 2003. [source]

Dynamical systems-based optimal control of incompressible fluids

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN FLUIDS, Issue 4 2004
Michael Hintermüller
Abstract For optimal control problems related to fluid flow the choice of an adequate cost functional for suppression of vortices is of significant importance. In this research we propose a cost functional based on a local dynamical systems characterization of vortices. The resulting functional is a non-convex function of the velocity gradient tensor. The resulting optimality system describing first order necessary optimality conditions is derived, a possible strategy for numerical realization of the optimal control problem is provided and a numerical feasibility study is conducted. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Active measurements of a mimo WiMAX-OFDM based system in reverberation chambers

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 10 2010
Adil Belhouji
Abstract Electromagnetic reverberation chambers can be used for multiple-input multiple-output (MIMO) systems testing.Currently, the tests focus on parameters such as correlation, diversity gain, efficiency, etc., by using a vector network analyzer. In contrast with these passive tests, a novel way of MIMO systems characterization is described in this article. It consists on evaluating bit error rate (BER) levels of a MIMO WiMAX-OFDM system according to the Signal-to-Noise Ratio (SNR) by establishing an active link between the transmitter and the receiver. The measurement process is set up in a reverberation chamber, where multipath frequency selective channels are emulated. The obtained results are compared to a reference case with single-input single-output (SISO) to evaluate the real improvements made by the studied system. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:2347,2352, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25465 [source]