2,508 research outputs found
Symmetry violations at BABAR
No full textContent from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Published under licence by IOP Publishing Ltd.2014 J. Phys.: Conf. Ser. 556 012042
(http://iopscience.iop.org/1742-6596/556/1/012042
MPC based optimal input design for nonlinear system identification
No full textA combined nonlinear model predictive control with extended Kalman filter strategy has been proposed for optimal input design. As the designed controller depend on the identified parameters, the achievable performance highly depends on the quality of the identified information. The degradation in achieving the desired control performance is quantified b y introducing an optimality criteria which minimize the error covariance matrix of the identified parameters. The major contribution is using the information of the system parameter at every sample time to improve the control performance at next time step. The the performance of the proposed algorithm is verified by numerical simulations for a example system
Optimal Input Design for Active Parameter Identification of Dynamic Nonlinear Systems
No full textThere are many important aspects to be considered while designing optimal excitation signal for system identification experiment in control applications. Active parameter identification is an important issue in system and control theory. In this dissertation, the problem of optimal input design for active parameter identification of dynamic nonlinear system is addressed. Real life physical systems are identified by excitation with a suitable input signal and observing the resulting output behavior of the system. It is important to choose the input signal intelligently in the sense that it is responsible to determine the accuracy and nature of the unknown system characteristics. This leads to a spurred interest in designing such an optimal excitation signals that can yield maximal information from the identification experiment. The information obtained from parameter identification is usually not accurate due to incomplete knowledge of the system, disturbance as exogenous inputs and noisy measurements. Hence, the input spectrum is designed in such a way that it can improve the system performance and shape the quality of obtained information. A welldesigned input signal can maximize the amount of information and reduce the experimental cost and time. The input signal is usually given some a-priori characteristics (knowledge on the pdf) so that “excitation” of the system is guaranteed. In this thesis, a closed-loop method is investigated which is able to improve the parameter identification on the basis of the actual system’s behavior. The effectiveness of the proposed algorithm is presented by the experimental results which corresponds to the perfect identification of the unknown parameter vector. The major technical contribution of this work is to propose an optimal feedback input design method for active parameter identification of dynamic nonlinear systems. The proposed framework can design such optimal excitation signals, considering the information from the identified parameters, that can maximize the
amount of information from the identified parameters, guarantee to meet the specified control performance and minimize some cost function of the error covariance matrix of the identified parameters. The problem is formulated in a receding horizon framework where extended Kalman filter is used for system identification and the optimal input is designed in a nonlinear model predictive control framework. In order to carry out a comparison study, also Unscented Kalman Filter and Gaussian Sum Filter are used for the active parameter identification of dynamic nonlinear system. Towards this end, a suitable optimality criterion related to the unknown parameters is proposed and motivated as an information measure. The aim of the optimal input design is to yield maximal information from the unknown system by minimizing the cost related to the unknown parameters while maintaining some process performance and satisfying the possible constraints. Simulations are performed to show the effectiveness of the proposed algorithm
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Rare B Decays at Babar
No full textThe author presents some of the most recent BABAR measurements for rare B decays. These include rate asymmetries in the B decays to K{sup (*)}l{sup +}l{sup -} and K{sup +}{pi}{sup -} and branching fractions in the B decays to l{sup +}{nu}{sub l}, K{sub 1}(1270){sup +}{pi}{sup -} and K{sub 1}(1400){sup +}{pi}{sup -}. The author also reports a search for the B{sup +} decay to K{sub S}{sup 0}K{sub S}{sup 0}{pi}{sup +}
Global software engineering: Identifying challenges is important and providing solutions is even better
No full textMuhammad Ali Babar, Christian Lesche
Reduction of stress induced bending in MEMS suspended membrane
No full textMEMS suspended membrane is used as moveable mirror in tunable Fabry-Pérot (FP) filters and tunable Lasers. Since the electrical and optical properties of the FP filters and VSCELs are highly dependent on the parallelism of the suspension holding the membrane in place, therefore, it has crucial role in the performance of these devices. Any bending in the suspensions results in displacement of the membrane which, in turn adversely affects the output properties of these devices. In our research work we present a multilayer suspension design with the aim to produce bend-less suspensions by compensating the stress of the materials and balancing the clock wise and counter clock wise moments within the multilayered structure. This new approach enables us to successfully reduce the displacement of the membrane to 76.7nm from several micrometer
Barrier function and terminal synergetic based controllers for the chemotherapy of brain tumor
No full textLumps formed by abnormal cell growth in the brain constitute brain tumors. Treatments differ depending on the specificity of the tumor and the condition of the patient; surgery, radiation therapy and targeted therapy are suggested for less severe tumors, while for severe tumors; chemotherapy is recommended. The last one, while being suggested and effective also in conjunction with surgery, has side effects that could be fatal. Therefore, it is mandatory to determine the appropriate dosage to obtain the desired effects without affecting healthy and immune cells. In this research work, advanced barrier function-based sliding mode and terminal synergetic-based controllers are designed to determine the amount of chemotherapy to eliminate tumor cells and maintain the right amount of healthy and immune cells. In particular, a barrier-based sliding mode controller is designed for dynamically controlling the chemotherapy drug for the tumor system, whereas the stability and convergence of the system are checked using the Lyapunov theory. The performance of the controller has been verified using MATLAB software based on different control parameters. The controller has remained successful in reducing the tumor cells and maintaining safe number of healthy and immune cells, showing favorable results in terms of steady-state error, over-under shoots, and rate of convergence
Stress Optimization for a MEMS Multilayer Fixed-Fixed Beam
No full textMicro-Electro Mechanical System (MEMS) based multi-layer fixed-fixed beams are used as suspensions to support the suspended membranes in tunable Fabry-Pérot Filters and tunable Vertical Cavity Surface Emitting Lasers. The electrical and optical performance of these devices depends highly on the parallelism of the suspensions holding the membrane in place. However, the residual stress in the suspension layer(s), upon relaxation, results in bending of the suspensions, which in turn results in displacement of the membrane. Therefore, the stress induced bending in the free-standing suspensions holding the membrane in place, must be minimized. A novel stress optimized multi-layer suspension system consisting of a fixed-fixed beam is designed in this work, whereby a tensile stressed material is sandwiched between two compressively stressed material films; such that the suspension layer system has an overall tensile film force, while an additional stress less layer is used to balance the clock-wise and counter clock-wise moments. The displacement of the central portion of the fixed-fixed beam is reduced from several micrometers to a mere 1.63 nm using this technique
Software Process Improvement barriers: a cross-cultural comparison
No full textAbstract not availableMahmood Niazi, Muhammad Ali Babar, June M. Verne
Fifty Years of Babar, Toledo, Ohio, 1985
No full textAuthor Laurent de Brunhoff signs Babar books for his fans at the Fifty Years of Babar exhibition at the Toledo Museum of Art in March of 1985. Terms associated with the photograph are: Babar (fictitious character) | Toledo Museum of Art (Toledo, Ohio) | Brunhoff, Jean de | Brunhoff, Laurent de | autographs | author
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