The quantum 1/f theory is applied to surface acoustic wave (SAW) LiNbO3 resonators. The theory has so far been applied only to quartz resonators. Here we are first considering the case in which the phonons are coheren...
The quantum 1/f theory is applied to surface acoustic wave (SAW) LiNbO3 resonators. The theory has so far been applied only to quartz resonators. Here we are first considering the case in which the phonons are coherent throughout the resonator volume. Then the quantum 1/f theory is applied to the general case of an arbitrary coherence length of the phonons, which may be large or small compared with the size of the resonator. This yields a 1/N factor in the expression of the power spectral density of resonance frequency fluctuations. The theory is further extended to include defect scattering along with the phonon scattering case exclusively considered so far.
This paper discusses the synthesis of stabilizing compensators for plants which can be represented using a Takagi-Sugeno (T-S) fuzzy model. The resulting compensator designs, called PDC controllers, are parameter depe...
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This paper discusses the synthesis of stabilizing compensators for plants which can be represented using a Takagi-Sugeno (T-S) fuzzy model. The resulting compensator designs, called PDC controllers, are parameter dependent and mirror the structure of the T-S plant model. This paper extends the existing work on state feedback PDC controllers by introducing the notion of a dynamic PDC controller. The paper contains two new results. The first result provides a more relaxed version of previously stated conditions which are sufficient for the existence of a quadratically stabilizing state feedback PDC controller. The second result provides analogous conditions which are sufficient for the existence of a quadratically stabilizing dynamic PDC controller.
Ultrathin devices have become important because they can be flexible and can be included on a plastic card. The low thickness increases the amount of surface scattering and scattering on dislocations and on other latt...
Ultrathin devices have become important because they can be flexible and can be included on a plastic card. The low thickness increases the amount of surface scattering and scattering on dislocations and on other lattice defects caused by bending. This goes hand in hand with a reduction of lattice scattering, both normal and umklapp or intervalley. For ultrasmall devices, the conventional quantum 1/f effect usually determines the low-frequency noise. This effect is proportional to the squared velocity change of the current carriers which is large in lattice scattering, and particularly large in umklapp or intervalley scattering. Therefore, we expect a reduction of 1/f noise with decreasing thickness of the devices. Nevertheless, there often will be an increase in noise, due to the general 1/N dependence on the number of carriers N which define the electric current and the noise current, and due to the additional noise caused by current inhomogeneities introduced by bending-related defects. Finally, as we show in this paper, the 1/N dependence is often compensated by the presence of a coherent quantum 1/f effect vestige.
This paper reports further development of the so-called ID Lyapunov equation based approach to the stability analysis of differential linear repetitive processes. In particular, it is shown that this approach leads to...
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This paper present a new effective algorithm for the optimal realization of digital controller structures using the delta operator for sampled data systems subject to Finite-Word-Length (FWL) constraints. The problem ...
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An important aspect of linear controller design is to clarify whether the design reaches the performance limit. Based on an industrial project-a high precision three-axis gyro test table (servo system), a paradigm is ...
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An important aspect of linear controller design is to clarify whether the design reaches the performance limit. Based on an industrial project-a high precision three-axis gyro test table (servo system), a paradigm is presented to demonstrate that the performance limit of the disturbance attenuation design of the servo system can be reached in a systematic way by using the μ -synthesis. Moreover, this paper reveals that the performance limit is determined by the bandwidth. This finding will help the designer to judge whether any given performance specification is achievable.
This paper addresses the benefits of integrating fault masking (FM) and fault detection and identification (FDI) methods to an embedded control system. It is shown that using a “smart” sensor in a Triple Modular Red...
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This paper addresses the benefits of integrating fault masking (FM) and fault detection and identification (FDI) methods to an embedded control system. It is shown that using a “smart” sensor in a Triple Modular Redundancy (TMR) configuration improves the system performance. Within the proposed hybrid system, “smart” sensors are used as redundant modules of the TMR configuration. A novel quality measure, which indicates the confidence level of a “smart” sensor output is used by a purpose-built voting algorithm to produce outputs. The proposed voting algorithm is a modification of weighted average voter, which produces results based on both the sensor output and the associated quality measure. This algorithm performs better than the conventional weighted average voter within a simple TMR configuration for low error ratios (<16). The main reason for this improvement is the capability of hybrid system to mask similar faults. Therefore, the proposed hybrid system produces more reliable results than the fault masking approach.
Robust control aims to account for model uncertainty in design. Traditional methods for robust control typically assume knowledge of hard bounds on the system frequency response. However, this does not match well with...
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Robust control aims to account for model uncertainty in design. Traditional methods for robust control typically assume knowledge of hard bounds on the system frequency response. However, this does not match well with system identification procedures which typically yield statistical confidence bounds on the estimated model. This paper explores a new procedure for obtaining a better match between robust control and system identification by using statistical confidence bounds for robust control design. It is shown that by changing the nominal design it is possible to reduce the overall variability from an a-priori specified desired performance. The proposed procedure is particularly straightforward and leads to a closed form solution for the final robust controller.
This paper present a new effective algorithm for the optimal realization of sampled-data SISO two order controller structures using the delta operator subject to Finite-Word-Length (FWL) constraints. The problem is fo...
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This paper present a new effective algorithm for the optimal realization of sampled-data SISO two order controller structures using the delta operator subject to Finite-Word-Length (FWL) constraints. The problem is formulated as a non-linear programming problem with a maximum of four independent variables to provide an easy and efficient optimization tool to solve such complex problems. Simulation results of the optimum FWL realizations of digital SISO two order controller structure applied to an electrohydraulic actuator system are presented to illustrate the effectiveness of the proposed strategy.
Pressure toasted peas and soybean flours were investigated in the ultraviolet (UV) and visible region by means of the photoacoustic (PA) spectroscopy and in near infrared (NIR) by the reflectance spectroscopy. Both te...
Pressure toasted peas and soybean flours were investigated in the ultraviolet (UV) and visible region by means of the photoacoustic (PA) spectroscopy and in near infrared (NIR) by the reflectance spectroscopy. Both techniques were shown capable of detecting the changes in flours caused by the heat treatment. The PA spectra of peas show pronounced differences in the UV range and at the absorption band of chlorophyll. In case of soybeans the PA spectra increase throughout the entire investigated region. The NIR spectra of both samples are similar with the effects of pressure toasting being largest at absorption bands of water, starch and protein.
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