Output feedback stabilization of switching discrete-time linear systems with parameter uncertainties     

Hamza Bibi  Fazia Bedouhene  Ali Zemouche  Hamid Reza Karimi  Houria Kheloufi 《Journal of The Franklin Institute》2017,354(14):5895-5918

This paper deals with observer-based control design for a class of switched discrete-time linear systems with parameter uncertainties. The main contribution of the paper is to propose a convenient way based on Finsler’s lemma to enhance the synthesis conditions, expressed in terms of Linear Matrix Inequalities (LMIs). Indeed, this judicious use of Finsler’s lemma provides additional decision variables, which render the LMIs less conservative and more general than all those existing in the literature for the same class of systems. Two numerical examples followed by a Monte Carlo evaluation are proposed to show the superiority of the proposed design technique.  相似文献   

Mutations in HNF1A Gene are not a Common Cause of Familial Young-Onset Diabetes in Iran     

Meysam Moghbeli  Bahram Naghibzadeh  Martha Ghahraman  Sedigheh Fatemi  Morteza Taghavi  Rahim Vakili  Mohammad Reza Abbaszadegan 《Indian journal of clinical biochemistry : IJCB》2018,33(1):91-95

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Overdamped and Underdamped Linear Dynamical Systems     

F.M. Reza 《Journal of The Franklin Institute》1982,313(5):287-298

Conditions are given for underdamped or overdamped linear dynamical systems in terms of loop matrix parameters, (√(C)R√(C)g,g)² ? 4(√(C)L√(C)g,g) for all [boxV]g[boxV] = 1, g ∈ H. These criteria are looked upon as natural generalizations of the elementary one-loop RLC series scalar criteria (R/2L)² ? 1/LC, when written in the more suggestive form: (√(C)R√(C))² ? 4√(C)L√(C). A simplified test for determining dynamical systems with all complex natural modes or all real modes are presented with additional comments.  相似文献   

Design and comparison of LQG/LTR and H_∞ controllers for a VSTOL flight control system     

Jafar Zarei  Allahyar Montazeri  Mohmmad Reza Jahed Motlagh  Javad Poshtan 《Journal of The Franklin Institute》2007,344(5):577-594

In this paper two robust controllers for a multivariable vertical short take-off and landing (VSTOL) aircraft system are designed and compared. The aim of these controllers is to achieve robust stability margins and good performance in step response of the system. LQG/LTR method is a systematic design approach based on shaping and recovering open-loop singular values while mixed-sensitivity H_∞ method is established by defining appropriate weighting functions to achieve good performance and robustness. Comparison of the two controllers show that LQG method requires rate feedback to increase damping of closed-loop system, while H_∞ controller by only proper choose the weighting functions, meets the same performance for step response. Output robustness of both controllers is good but H_∞ controller has poor input stability margin. The net controller order of H_∞ is higher than the LQG/LTR method and the control effort of them is in the acceptable range.  相似文献   

How do self-efficacy,contextual variables and stressors affect teacher burnout in an EFL context?     

Reza Khani  Alireza Mirzaee 《教育心理学》2015,35(1):93-109

This study was an attempt to investigate the relationships among stressors, contextual variables, self-efficacy and teacher burnout in Iran as an EFL (English as a Foreign Language) context. A battery of questionnaires was administered to 216 English language teachers of private language institutes. Using Amos version 20, structural equation modelling was run to examine the proposed model of the study. The findings showed that contextual variables could directly cause teacher burnout. They could also do so indirectly by giving rise to stressors, which would in turn increase burnout. The results also highlighted the possible direct and indirect role of self-efficacy in reducing teacher burnout. We argue that self-efficacy could function as a mediator or moderator variable which would reduce the negative effects of contextual variables and stressors on teacher burnout. The results of the present study have important implications for various stakeholders in pedagogy.  相似文献   

An integrated microfluidic chip for immunocapture,preconcentration and separation of β-amyloid peptides     

Reza M. Mohamadi  Zuzana Svobodova  Zuzana Bilkova  Markus Otto  Myriam Taverna  Stephanie Descroix  Jean-Louis Viovy 《Biomicrofluidics》2015,9(5)

We present an integrated microfluidic chip for detection of β-amyloid (Aβ) peptides. Aβ peptides are major biomarkers for the diagnosis of Alzheimer''s disease (AD) in its early stages. This microfluidic device consists of three main parts: (1) An immunocapture microcolumn based on self-assembled magnetic beads coated with antibodies specific to Aβ peptides, (2) a nano-porous membrane made of photopolymerized hydrogel for preconcentration, and (3) a microchip electrophoresis (MCE) channel with fluorescent detection. Sub-milliliter sample volume is either mixed off-chip with antibody coated magnetic beads and injected into the device or is injected into an already self-assembled column of magnetic beads in the microchannel. The captured peptides on the beads are then electrokinetically eluted and re-concentrated onto the nano-membrane in a few nano-liters. By integrating the nano-membrane, total assay time was reduced and also off-chip re-concentration or buffer exchange steps were not needed. Finally, the concentrated peptides in the chip are separated by electrophoresis in a polymer-based matrix. The device was applied to the capture and MCE analysis of differently truncated peptides Aβ (1–37, 1–39, 1–40, and 1–42) and was able to detect as low as 25 ng of synthetic Aβ peptides spiked in undiluted cerebrospinal fluid (CSF). The device was also tested with CSF samples from healthy donors. CSF samples were fluorescently labelled and pre-mixed with the magnetic beads and injected into the device. The results indicated that Aβ1-40, an important biomarker for distinguishing patients with frontotemporal lobe dementia from controls and AD patients, was detectable. Although the sensitivity of this device is not yet enough to detect all Aβ subtypes in CSF, this is the first report on an integrated or semi-integrated device for capturing and analyzing of differently truncated Aβ peptides. The method is less demanding and faster than the conventional Western blotting method currently used for research.  相似文献   

An alternative approach to describing agility in sports through establishment of a relationship between velocity and radius of curvature     

Ahmed Reza Arshi  Sina Mehdizadeh  Keith Davids 《Journal of sports sciences》2015,33(13):1349-1355

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Performance of gymnastics skill benefits from an external focus of attention     

Reza Abdollahipour  Gabriele Wulf  Rudolf Psotta  Miriam Palomo Nieto 《Journal of sports sciences》2015,33(17):1807-1813

The present study was designed to fill a gap in the literature on attentional focus and sports performance. Specifically, in contrast to most previous studies in which an external focus was directed at an implement, we used a gymnastics skill that did not involve the use of an implement. Furthermore, while most studies used only outcome measures of performance, we also assessed movement quality. Twelve-year-old gymnasts performed a maximum vertical jump with a 180-degree turn while airborne, with their hands crossing in front of their chest during the turn under three different focus conditions. Under the external focus condition, participants were asked to focus on the direction in which a tape marker, which was attached to their chest, was pointing after the turn. Under the internal focus condition, they were asked to focus on the direction in which their hands were pointing after the turn. Under the control condition, no focus instructions were given. The external focus condition resulted in both superior movement form and greater jump height than did the other two conditions, which produced comparable results. The present findings show that, similar to other tasks, the performance of form-based skills can be enhanced relatively easily by appropriate external focus instructions.  相似文献   

A Global Energy Theorem for Linear Systems     

F.M. Reza 《Journal of The Franklin Institute》1982,313(2):97-105

A fundamental theorem and inequalities were derived earlier by the author describing arithmetic-geometric means and convex behaviour of the active energy dissipated by arbitrary linear reciprocal passive systems. These results are extended to give a new global theorem concerning bounds of energy for arbitrary linear active or passive, reciprocal or non-reciprocal systems.  相似文献   

Ercikan,K., & Pellegrino,J. W. Eds. (2017). Validation of Score Meaning for the Next Generation of Assessments: The Use of Response Processes. New York,NY: Routledge.     

Reza Neiriz 《Journal of Educational Measurement》2020,57(1):152-155

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