Search results for "control system"
showing 10 items of 971 documents
Implementation on NI-SOM sbRIO-9651 and Experimental Validation of Multi-Carrier PWM Techniques for Three-Phase Five Level Cascaded H-Bridge Inverter
2021
Multilevel Power Inverters (MPIs) represent a valid solution to improve the performances of energy production systems from renewable energy sources. Furthermore, the use of novel FPGA control systems allows simplifying the implementation of multicarrier PWM techniques for MPIs with computational benefits. This paper describes the implementation of several multicarrier PWM techniques on NI-SOM sbRIO-9651 for the control of a three-phase five-level cascaded H-bridge inverter. In detail, sbRIO-9651 is a control system in the field of Power Electronics and Drives (PED) programmable in the LabVIEW graphical programming environment. The paper is focused on modulation techniques implementation, te…
A new observable to measure the top-quark mass at hadron colliders
2013
A new method to measure the top-quark mass in high energetic hadron collisions is presented. We use theoretical predictions calculated at next-to-leading order accuracy in quantum chromodynamics to study the ( normalized) differential distribution of the t (t) over bar + 1-jet cross section with respect to its invariant mass root s(t (t) over barj). The sensitivity of the method to the top-quark mass together with the impact of various theoretical and experimental uncertainties has been investigated and quantified. The new method allows for a complementary measurement of the top-quark mass parameter and has a high potential to become competitive in precision with respect to established appr…
Review and comparison of experimental techniques used for determination of thin film electro-optic coefficients
2015
The results of electro-optic coefficient measurements performed with three commonly applied techniques used to assess electro-optic coefficients: the Mach–Zehnder, the Teng–Man, and the attenuated total reflectance technique are reported. It is shown that the signal obtained by the Mach–Zehnder and Teng–Man techniques is strongly influenced by the multiple internal reflection and piezo- and electrostrictive thickness change effects, which in our opinion have not been addressed sufficiently in the literature. A novel approach based on using Abeles matrix formalism is implemented for the retrieval of electro-optic coefficients from experimental data. The measurement results, errors, and compa…
One-Class Classifiers : A Review and Analysis of Suitability in the Context of Mobile-Masquerader Detection
2007
One-class classifiers employing for training only the data from one class are justified when the data from other classes is difficult to obtain. In particular, their use is justified in mobile-masquerader detection, where user characteristics are classified as belonging to the legitimate user class or to the impostor class, and where collecting the data originated from impostors is problematic. This paper systematically reviews various one-class classification methods, and analyses their suitability in the context of mobile-masquerader detection. For each classification method, its sensitivity to the errors in the training set, computational requirements, and other characteristics are consi…
Current-Based Measurement Technique for High Sensitivity Detection of Resistive Bridges With External Balancing Through Control Voltages
2017
We present a novel approach based on differential measurements of dc currents with very high sensitivity suitable for the detection of very small variations of resistors in Wheatstone full-bridge configurations. External control voltages allow for the compensation of the bridge unbalancing avoiding the need of changing its elements so making the solution suitable for integrated sensor systems. The proposed current-based measurement technique has been implemented through three different circuits, in transimpedance configuration and without the use of any further amplification stage, employing only two active blocks that allow for a very high integration level. The main characteristics of the…
On the sensitivity of bridge seismic response with local soil amplification
1998
The paper presents a numerical sensitivity study of the local site effects on structural response. Following a recently developed model of spatial coherency and a concept of a simple site coefficient the local site effects are modelled as filtrations of excitation processes with a frequency shift. An analysis of a bridge response with supports founded on different soils is carried out. The joint effects of dynamic response and pseudostatic motion are considered. Two types of response are analysed: longitudinal and transverse. The differences between dynamic displacements and force responses are pointed out.
Exploring management control system typologies : an organisation-level view
2020
PurposeManagement controls are the processes and mechanisms managers use to influence the behaviour of individuals and groups towards the organisation’s objectives and goals. Discrete management controls and management control system (MCS) frameworks have been extensively researched, but there is little research on organisation-level MCS types. This study aims to identify organisation-level MCS types.Design/methodology/approachThis study draws on the MCS type literature, the competing values framework and the upper echelons theory to form organisation effectiveness and top management team constructs to characterise firms. Cluster analysis was used to group a sample of 318 firm-years into MC…
Ultrasonic guided wave propagation in long bones with varying cortical thickness
2009
The propagation of ultrasonic guided wave (GW) in the long bone is very sensitive to the bones' shapes, properties and cortical thicknesses (CTh). Most of the previous studies on the GW propagation in long bones mainly focused on the bones with uniform CTh. However, it is necessary to understand the impacts of CTh variation, such as mode conversion. Therefore, an adequate analysis on GW propagating in long bones with varying CTh is essential for the precise calibration of the quantitative measurement of it. The aim of this study is to use a modified boundary element method (BEM) to analyze the GW propagation characteristics in long bones with varying CTh. Numerical analysis implemented by t…
Design of the stabilization control system of a high-speed craft
2016
In this paper, the main causes of technical malfunction of a hydrofoil was analyzed. In particular, a preliminary analysis evaluates the economic impact for the navigation company of the periodical maintenance related to the keeping of the vessel in dry dock. The study demonstrated that the main critical points are focused on the fragility of the stabilization control system. The increasing of operating costs has motivated the realization of a study aimed at redesigning the stabilization system. The continuing failure of the stabilization system (usually in water-immersed) severely limits the use of the high-speed craft. The proposed design solution considers the positioning of the control …
Structural Vibration Control for a Class of Connected Multistructure Mechanical Systems
2012
Published version of an article from the journal: Mathematical Problems in Engineering. Also available from the publisher:http://dx.doi.org/10.1155/2012/942910 A mathematical model to compute the overall vibrational response of connected multistructure mechanical systems is presented. Using the proposed model, structural vibration control strategies for seismic protection of multibuilding systems can be efficiently designed. Particular attention is paid to the design of control configurations that combine passive interbuilding dampers with local feedback control systems implemented in the buildings. These hybrid active-passive control strategies possess the good properties of passive contro…