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Oseledets splitting and invariant manifolds on fields of banach spaces
, Article Journal of Dynamics and Differential Equations ; 2021 ; 10407294 (ISSN) ; Riedel, S ; Sharif University of Technology
Springer
2021
Abstract
We prove a semi-invertible Oseledets theorem for cocycles acting on measurable fields of Banach spaces, i.e. we only assume invertibility of the base, not of the operator. As an application, we prove an invariant manifold theorem for nonlinear cocycles acting on measurable fields of Banach spaces. © 2021, The Author(s)
A dynamical theory for singular stochastic delay differential equations i: linear equations and a multiplicative ergodic theorem on fields of banach spaces
, Article SIAM Journal on Applied Dynamical Systems ; Volume 21, Issue 1 , 2022 , Pages 542-587 ; 15360040 (ISSN) ; Riedel, S ; Scheutzow, M ; Sharif University of Technology
Society for Industrial and Applied Mathematics Publications
2022
Abstract
We investigate singular stochastic delay differential equations (SDDEs) in view of their long-time behavior. Using Lyons's rough path theory, we show that SDDEs can be solved pathwise and induce a continuous stochastic flow on the space of (Gubinelli's) controlled paths. In the language of random dynamical systems, this result shows that SDDEs induce a continuous cocycle on random fibers, or, more precisely, on a measurable field of Banach spaces. We furthermore prove a multiplicative ergodic theorem (MET) on measurable fields of Banach spaces that applies under significantly weaker structural and measurability assumptions than preceding METs. Applying it to linear SDDEs shows that the...
Correction to: Oseledets Splitting and Invariant Manifolds on Fields of Banach Spaces (Journal of Dynamics and Differential Equations, (2021), 10.1007/s10884-021-09969-1)
, Article Journal of Dynamics and Differential Equations ; 2021 ; 10407294 (ISSN) ; Riedel, S ; Sharif University of Technology
Springer
2021
Abstract
The original version of this article unfortunately contained a typo in co-author name. The author name is “Mazyar Ghani Varzaneh” instead it was published incorrectly as “M. Mazyar Ghani Varzaneh”. © 2021, Springer Science+Business Media, LLC, part of Springer Nature
Oseledets splitting and invariant manifolds on fields of banach spaces
, Article Journal of Dynamics and Differential Equations ; Volume 35, Issue 1 , 2023 , Pages 103-133 ; 10407294 (ISSN) ; Riedel, S ; Sharif University of Technology
Springer
2023
Abstract
We prove a semi-invertible Oseledets theorem for cocycles acting on measurable fields of Banach spaces, i.e. we only assume invertibility of the base, not of the operator. As an application, we prove an invariant manifold theorem for nonlinear cocycles acting on measurable fields of Banach spaces. © 2021, The Author(s)
Correction to: Oseledets splitting and invariant manifolds on fields of banach spaces (journal of dynamics and differential equations, (2023), 35, 1, (103-133), 10.1007/s10884-021-09969-1)
, Article Journal of Dynamics and Differential Equations ; Volume 35, Issue 1 , 2023 , Pages 983- ; 10407294 (ISSN) ; Riedel, S ; Sharif University of Technology
Springer
2023
Abstract
A correction to this paper has been published: https://doi.org/10.1007/s10884-021-09990-4 © 2021, Springer Science+Business Media, LLC, part of Springer Nature
Dynamical Properties of Rough Delay Equations
, Ph.D. Dissertation Sharif University of Technology ; Zohuri Zangeneh, Bijan (Supervisor)
Abstract
In this monograph, we investigate the long-time behavior of stochastic delay equations. Our approach is random dynamical systems, and we solve our equation in the rough path point of view. Namely, we deal with the singular case, i.e., when the delay terms also are appearing in the diffusion part. Although we can solve the equation using the classical tools of stochastic analysis, the main obstacle is the lack of flow property. More precisely, the solution does not depend continuously on the initial value. To solve this problem, we define this property differently. We will show how we can generate a flow property on fields of Banach spaces using rough path theory. As a consequence, we prove...
A comprehensive architecture platform for smarter universities
, Article 2023 28th International Computer Conference, Computer Society of Iran, CSICC 2023 ; 2023 ; 979-835033819-5 (ISBN) ; Merikhi, B ; Saberi Varzaneh, M ; Alam Varzaneh Isfahani, M. H ; Habibi Kalahroodi, H ; Fatemipour Sharabiany, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
One of the most crucial infrastructure requirements of integrated systems is designing and providing a comprehensive architecture for implementation, support and improvement of their smart services or platforms. And without exception, smart University would also require a responsive architecture for the integration and consolidation of its current and future systems and services. Providing higher level of academic services, integration and consolidation support, and cost accounting (including 'cloud storage', 'computing', 'network communication and bandwidth' and energy consumption) can be placed as pivotal issues among smart university services. In this article, a basic definition of a...
Distributed algorithms for power saving optimization in sensor network
, Article Proceedings of the 8th WSEAS International Conference on Data Networks, Communications, Computers, DNCOCO '09, 7 November 2009 through 9 November 2009 ; 2009 , Pages 109-115 ; 9789604741342 (ISBN) ; Mousavi, M ; Movaghar, A ; Sharif University of Technology
2009
Abstract
Sensor networks have a wide range of potential and practical application. A sensor network consists of a large number of tiny, low power and short-living sensors. Some sensor network applications require k-coverage to ensure the quality of surveillance. Meanwhile, energy is another primary concern for sensor networks. In this dissertation, an algorithm proposed which groups sensors in to disjoint subsets. Every subset cans k-cover the whole area. The subsets are scheduled to work successively. Therefore, the network lifetime is prolonged. Furthermore, sensing range is fixed. Also another algorithm, proposed which constructs some non-disjoint subsets, and in each active subset, each sensor...
An internally coded time-hopping spread-time CDMA scheme for UWB systems and its performance analysis
, Article 2007 IEEE Radio and Wireless Symposium, RWS, Long Beach, CA, 9 January 2007 through 11 January 2007 ; 2007 , Pages 511-514 ; 9781424404452(ISBN) ; Nasiri Kenari, M ; Sharif University of Technology
2007
Abstract
We consider an internally coded multiple access technique for Ultra Wide-Band systems which combines time-hopping (TH) and spread-time (ST) techniques using a super-orthogonal encoder. In this method, the duration of each bit is divided into Ns frames. The outputs of a superorthogonal encoder and a PN sequence specify the frame number, in which the data is transmitted in spread-time CDMA form using the second PN sequence. We consider soft decision before Viterbi decoding at the receiver. We obtain the performance of the proposed method. We also consider the uncoded ST-CDMA system and compare its performance with our method. The results indicate that our method has much more better...
Performance analysis of an internally coded MC-FH-CDMA system
, Article 2007 IEEE International Conference on Telecommunications and Malaysia International Conference on Communications, ICT-MICC 2007, Penang, 14 May 2007 through 17 May 2007 ; February , 2007 , Pages 23-28 ; 1424410940 (ISBN); 9781424410941 (ISBN) ; Nasiri Kenari, M ; Sharif University of Technology
2007
Abstract
We consider an internally coded scheme for multicarrier frequency-hopping CDMA (MC-FH-CDMA) communication systems. In this method, the total bandwidth is partitioned into Ns1 disjoint bands and each band is also segmented into Ns2 subbands. Based on the super-orthogonal encoder output and a pseudorandom (PN) sequence, one of the Ns1 bands is selected. Then, the data is transmitted in that band in the form of multicarrier frequency-hopping technique using BPSK modulation. At the receiver front end, we use soft detector, then we apply Viterbi decoding algorithm. We evaluate the performance of the proposed method. The results indicate that our method outperforms the previously presented uncoded...
The most optimal barrier height of InGaN light-emitting diodes
, Article Applied Physics A: Materials Science and Processing ; Volume 127, Issue 2 , 2021 ; 09478396 (ISSN) ; Faez, R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this paper, a novel structure is presented in order to decrease the polarization charges of quantum wells. The main purpose of this design is to make electron and hole wavefunctions closer to each other and to increase overlap integral following an increase of radiative recombination rates and internal quantum efficiency. Furthermore, carriers will be increased and become more balanced and identical which leads to an increase in efficiency of light-emitting diodes. The improvement of radiative recombination rates is studied in new structures. Energy bands diagram, carriers density, current density–voltage, and power density–current density are used to demonstrate the superior performance...
The most optimal barrier height of InGaN light-emitting diodes
, Article Applied Physics A: Materials Science and Processing ; Volume 127, Issue 2 , 2021 ; 09478396 (ISSN) ; Faez, R ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this paper, a novel structure is presented in order to decrease the polarization charges of quantum wells. The main purpose of this design is to make electron and hole wavefunctions closer to each other and to increase overlap integral following an increase of radiative recombination rates and internal quantum efficiency. Furthermore, carriers will be increased and become more balanced and identical which leads to an increase in efficiency of light-emitting diodes. The improvement of radiative recombination rates is studied in new structures. Energy bands diagram, carriers density, current density–voltage, and power density–current density are used to demonstrate the superior performance...
Attitude and Deformation Estimation of Flexible Satellite Using Magnetometer and Sun Sensor
, M.Sc. Thesis Sharif University of Technology ; Asadian, Nima (Supervisor)
Abstract
The estimation of attitude and deformation of a flexible satellite using magnetometer and sun sensor data are studied in this thesis. To this end, the dynamical differential equations of the flexible satellite have been derived using Lagrange’s equation. These equations of motion are then utilized for the purpose of simulation and verification. After introducing the measurements equations, the observability of the satellite with flexible panels has been evaluated. Afterward, the attitude of the satellite body and deformation of the flexible panels have been estimated by EKF (Extended Kalman Filter) as well as UKF (Unscented Kalman Filter). The results show that the estimations using UKF are...
Attitude and deformation coupled estimation of flexible satellite using low-cost sensors
, Article Advances in Space Research ; Volume 69, Issue 1 , 2022 , Pages 677-689 ; 02731177 (ISSN) ; Assadian, N ; Varatharajoo, R ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Solar panel flexibility plays an important role in the attitude control of satellites. Therefore, traditionally the deformations of flexible solar panels are measured with a series of sensors along the panels itself. This paper presents a novel maiden attempt to simultaneously estimate the attitude and deformation of a flexible satellite using only 2 low-cost attitude sensors namely the sun sensor and magnetometer measurements. The flexible satellite is considered as a central rigid body with two attached flexible panels in order to derive the governing dynamic equations based on the Lagrange's equation. Both Extended Kalman filter (EKF) and Unscented Kalman Filter (UKF) are employed for the...
An Introduction to Langlands Program
, M.Sc. Thesis Sharif University of Technology ; Pournaki, Mohammadreza (Supervisor)
Abstract
The Weil group WF is assigne to every local field F. Langlands Correspondence is a bijetion between semisimple two-dimensional Deligne representations of Weil Group WF and irreducible representations of GL2(F) which fixes assigned L-functions and local constants. In this thesis we have classified an important class of irreducible representations of GL(2) over local fields called Principal Series. We also tried to give a taste of Langlands Correspondence to the reader. First we explain preliminaries and introduce locally profinite groups and their smooth representations. Then we classify representations of GL2(F) when F is finite. Then we study GL2(F) when F is a local field. Finally we...
Simulation and Implementation of Active Energy Management Algorithm on Residential Photovoltaic System with Storage
, M.Sc. Thesis Sharif University of Technology ; Abbaspour, Ali (Supervisor)
Abstract
In majority of the (standalone or grid-connected) PV Systems, predefined rule-based algorithms are utilized in order to manage and control the flow of power. The function of these algorithms is to send the generated energy from solar panels either to load for consumption, or to battery for storage, or to the grid for sale. Their performance is based on predefined instructions and regardless of load change and consumption patterns. Therefore the total efficiency of these systems depend greately upon individual user’s load type and consumption pattern. In current research, an optimum and dynamic energy management algorithm is proposed using dynamic programming (DP) method, in order to increase...
Approximation Algorithms for Clustering Points in the Data Stream Model
, M.Sc. Thesis Sharif University of Technology ; Zarrabi Zadeh, Hamid (Supervisor)
Abstract
The k-center problem—covering a set of points using k congruent balls with minimum radius—is a well-known clustering model in computer science with a wide range of applications. The k-center is a well known NP-Hard problem. In this thesis, we focus on the k-center problem with outliers in high dimensional data streams. Due to increase in data size, we focus on the data stream model of the problem. Moreover, in real-world applications, where input points are noisy, it is very important to consider outliers. In this thesis, we study 1-center and 2-center with outliers in high dimensional data streams in Euclidean space. We provide a 1:7-approximation streaming algorithm for 1-center with z...
Existence of Arithmetic Progressions in Subsets of Natural Numbers
, M.Sc. Thesis Sharif University of Technology ; Rastegar, Arash (Supervisor) ; Hatami Varzaneh, Omid (Supervisor)
Abstract
Szemeredi's theorem is one of the significant theorems in additive combinatorics which was started by Van Der Waerden's theorem in 1927. Erdos and Turan conjectured generalized versions of Van Der Waerden's theorem in several ways included Szemeredi's theorem. In 1975 Szemeredi proved the conjecture using complicated combinatorial methods. In 1977 H. Furstenberg proved Szemeredi's theorem via the Ergodic theory approach which led to prove polynomial Szemeredi's theorem and multi-dimensional Szemeredi's theorem. The Ergodic approach is the only known approach so far to these generalizations of this theorem which is named Ergodic Ramsey theory and led to some other problems in Ergodic theory...
Synthesis of Sr3Fe2O7and Investigation of the Effect of Pr in Sr Site and Co in Fe Site as a Dopant on the Microstructure and its Function as a Solid Oxide Fuel Cathode
, M.Sc. Thesis Sharif University of Technology ; Nemati, Ali (Supervisor) ; Golmohammad, Mohammad (Supervisor)
Abstract
Nowday, one of the important goals of researchers is to develop and improve the properties of intermediate tempreture solid oxide fuel cells with range of 600-800˚C. Therefore, choosing the right material as a cathode with good performance in this temperature range is very important. For this purpose, various materials with ionic and electron conductivity mixtures (MIECs) are used, especially oxides with a Radelsden-Paper structure. These oxides are shown by the formula An+1BnC3n+1, which are actually composed of a combination of perovskite layers (ABO3) that are alternately superimposed between two layers of rock salt (AO). In the present study, Sr3Fe2O7 powder with different amounts...
Improved salinity tolerance in early growth stage of maize through salicylic acid foliar application
, Article Italian Journal of Agronomy ; Volume 16, Issue 3 , 2021 ; 11254718 (ISSN) ; Khan, I ; Chattha, M. U ; Hassan, M. U ; Barbanti, L ; Calone, R ; Ali, M ; Majeed, S ; Ghani, M. A ; Batool, M ; Izzat, W ; Usman, S ; Sharif University of Technology
Page Press Publications
2021
Abstract
Soil salinity threatens agricultural production worldwide by constraining plant growth and final crop yield. The early stages are most sensitive to salinity, in response to which salicylic acid (SA) has demonstrated beneficial effects in various plant species. Based on this, a maize (Zea mays L.) pot experiment was set up combining three levels of soil salinity (0, 6 and 12 dS m–1), obtained through NaCl addition, with three levels of SA (0, 300 and 600 mM), applied by leaf spraying 20 days after seedling emergence. Fifteen days later, the following traits were assessed: morphology (plant height, leaf number), growth (root and shoot dry weight), leaf water status [relative water content...