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Accelerating Physics-Informed Neural Network Training Time for Fluid Dynamic Applications
, M.Sc. Thesis Sharif University of Technology ; Bijarchi, Mohammad Ali (Supervisor)
Abstract
This research introduces an accelerated training approach for Vanilla Physics-Informed Neural Networks (PINNs) that addresses three factors affecting the loss function: the initial weight state of the neural network, the ratio of domain to boundary points, and the loss weighting factor. The proposed method involves two phases. In the initial phase, a unique loss function is created using a subset of boundary conditions and partial differential equation terms. Furthermore, we introduce preprocessing procedures that aim to decrease the variance during initialization and choose domain points according to the initial weight state of various neural networks. The second phase resembles...
A novel design of the KASUMI block cipher using one-hot residue number system
, Article Middle East Journal of Scientific Research ; Volume 11, Issue 8 , 2012 , Pages 1078-1086 ; 19909233 (ISSN) ; Sharif University of Technology
2012
Abstract
The KASUMI block cipher is used for the cellular communications networks and safety of many wireless standards. Third generation cellular network technology (3G) permits to transmit information, voice and video at very high data rates never seen before that will revolutionize personal communications and information exchange. On the other hand, Residue Number System (RNS) is a modular representation and is evidenced to be serviceable equipment in many applications which need high-speed computations and high-performance components. RNS is a non-weighted and integer number system that can support secure, highspeed, low-power, parallel and carry-free arithmetic. For attaining the most...
Reliable and high-speed KASUMI block cipher by residue number system code
, Article World Applied Sciences Journal ; Volume 17, Issue 9 , 2012 , Pages 1149-1158 ; 18184952 (ISSN) ; Sharif University of Technology
2012
Abstract
Third generation cellular network technology (3G) can revolutionize communications and data exchanges between many people in a more overwhelming fashion than 2G and 2.5G networks did. The 3G UMTS, the 3G GSM and the 3G GPRS rely on the KASUMI block cipher. Therefore, increasing speed, decreasing power consumption and error detection/correction are the major concerns of the KASUMI algorithm and its generation. On the other hand, Residue Number System is a non-weighted number system and it is currently considered as an important method for high-speed, low-power, parallel and carry-free arithmetic realizations. Redundant Residue Number System is an extension of RNS that also supports error...
Business Process Oriented Software Engineering
, M.Sc. Thesis Sharif University of Technology ; Habibi, Jafar (Supervisor)
Abstract
Enterprises are founded according to their business processes based on its targets. For implementing an Information System, first it is required to analyze, design and model of the processes based on a specific methodology.The methodologies of software engineering usually used to be function oriented however object oriented is usual and practical todays. Analyzing the business processes according to one of these two concepts has some problems, however merging these two concepts, makes a powerful method in analyzing and designing of a system more easily and accurately.Some software development methodologies consider these two aspects in a way, however working with them has many complexities...
A frequency domain proof for the equivalence of the maximally flat FIR fractional delay filter and the Lagrange interpolator
, Article Digital Signal Processing: A Review Journal ; Volume 21, Issue 1 , 2011 , Pages 13-16 ; 10512004 (ISSN) ; Sharif University of Technology
2011
Abstract
One of the most important properties of the maximally flat (MF) FIR fractional delay (FD) filter is its equivalence with the Lagrange interpolator for uniformly sampled signals. In this article, to provide the required background for the reader, we first propose a straightforward algebraic proof for this equivalence. This proof is given by simply demonstrating that the system of linear equations governing the maximally flatness property of this filter is the same as the one from which the coefficients of the Lagrange interpolator are computed. We then present the main contribution of the paper, which is a frequency domain proof for the same equivalence. In contrast with its classic...
Numerical study of aero- acoustic characteristics in an automotive air-intake system
, Article 42nd International Congress and Exposition on Noise Control Engineering 2013, INTER-NOISE 2013: Noise Control for Quality of Life ; Volume 7 , 2013 , Pages 5990-5999 ; 9781632662675 (ISBN) ; Beigmoradi, S ; Sharif University of Technology
OAL-Osterreichischer Arbeitsring fur Larmbekampfung
2013
Abstract
Compartment noise has gained significant importance to meet customer expectation. One of the dominant sources of noise from whole engine as a system is the one which is induced from fresh air intake. Geometrical features in air induction systems (AIS) airflow path are often responsible for unusual noise due to the complex air flow structure and its interaction with the internal acoustic field. To reduce air intake noise basically resonator and expansion chamber are used on automotive vehicles. Resonators are widely used for noise reduction of air induction systems. Although, airflow bench tests are faster to evaluate various alternate design geometries, understanding the mechanism of such...
Low-order adaptive half-sample interpolators
, Article Electronics Letters ; Volume 46, Issue 13 , June , 2010 , Pages 897-898 ; 00135194 (ISSN) ; Sharif University of Technology
2010
Abstract
Although the fractional delay filtering literature is full of design methods and implementation techniques for fractional sample interpolators, a fundamental need for the proposition of low-order efficient designs still strongly exists. Proposed is such a system for half-sample interpolation. In contrast to the typical systems studied in the literature for fractional delay filtering, the system proposed continuously adapts its interpolation kernel to the statistical variations of the input signal, and this is in fact the reason for it being needless of having a high order. Satisfactory performance of the proposed structure has been demonstrated via simulation
Wideband maximally flat fractional-delay allpass filters
, Article Electronics Letters ; Volume 46, Issue 10 , May , 2010 , Pages 722-723 ; 00135194 (ISSN) ; Sharif University of Technology
2010
Abstract
The maximally flat (MF) fractional-delay (FD) allpass filter, also known as Thiran's allpass filter, is one of the most popular IIR FD systems which is typically deployed in its causal forms. It is shown that if this causality constraint is removed, MFFD allpass filters with considerably wider bandwidths can be obtained. In many applications this extra bandwidth is worth having a non-causal system
Equivalence of the Lagrange interpolator for uniformly sampled signals and the scaled binomially windowed shifted sinc function
, Article Digital Signal Processing: A Review Journal ; Volume 19, Issue 5 , 2009 , Pages 838-842 ; 10512004 (ISSN) ; Sharif University of Technology
2009
Abstract
The maximally flat (MF) fractional delay (FD) filter which is in fact a Lagrange interpolator for uniformly sampled signals, has previously been shown to be equal to the scaled binomially windowed shifted version of the sinc function; the ideal interpolation kernel for band-limited signals. In this paper, another proof for this equivalence is presented. Unlike its counterparts available in the literature, the proof given here is neither strictly algebraic, nor deploys the explicit coefficient formulas of the MFFD filter. It follows a frequency domain approach based on the definition of this filter instead, and aims to provide more insight into the corresponding equivalence. © 2009 Elsevier...
Equivalence of the Lagrange interpolator for uniformly sampled signals and the scaled binomially windowed shifted sinc function
, Article Digital Signal Processing: A Review Journal ; Volume 19, Issue 5 , 2009 , Pages 838-842 ; 10512004 (ISSN) ; Sharif University of Technology
2009
Abstract
The maximally flat (MF) fractional delay (FD) filter which is in fact a Lagrange interpolator for uniformly sampled signals, has previously been shown to be equal to the scaled binomially windowed shifted version of the sinc function; the ideal interpolation kernel for band-limited signals. In this paper, another proof for this equivalence is presented. Unlike its counterparts available in the literature, the proof given here is neither strictly algebraic, nor deploys the explicit coefficient formulas of the MFFD filter. It follows a frequency domain approach based on the definition of this filter instead, and aims to provide more insight into the corresponding equivalence. © 2009 Elsevier...
Half-band FIR fractional delay filters with closed-form coefficient formulas and modular implementation based on Lagrange interpolators
, Article Signal Processing ; Volume 88, Issue 12 , 2008 , Pages 2913-2916 ; 01651684 (ISSN) ; Sharif University of Technology
2008
Abstract
The Taylor series-based representation of the maximally flat (MF) FIR fractional delay (FD) filter is manipulated to obtain a FD filter with a wider band-width. The band-width of the proposed filter can approach π / 2 rads / s, which is 1.5 times that of the prototype one. The design has closed-form coefficient formulas as well as a modular implementation. These two properties make it a practically favourable one. © 2008 Elsevier B.V. All rights reserved
Erratum to: "Fast design of relatively wide band fractional delay all-pass filters" [Signal Process. 88 (3) (2008) 612-623] (DOI:10.1016/j.sigpro.2007.09.006)
, Article Signal Processing ; Volume 88, Issue 4 , 2008 , Pages 1082- ; 01651684 (ISSN) ; Sharif University of Technology
2008
Abstract
A fast and simple procedure for designing relatively wide band fractional delay (FD) all-pass filters is proposed and filters designed based on it are compared to those designed using Thiran’s method, which is one of the simplest, fastest and widely used approaches in designing FD all-pass filters. It is shown that filters designed using the introduced method have wider fractional group delay (fgpd) bandwidths compared to those obtained via Thiran’s technique, as well as some other desired properties. The designed filters are also demonstrated to be stable for several pairs of filter orders and fgpd values. r2007 Elsevier B.V. All rights reserved
Fast design of relatively wide band fractional delay all-pass filters
, Article Signal Processing ; Volume 88, Issue 3 , 2008 , Pages 612-623 ; 01651684 (ISSN) ; Sharif University of Technology
Elsevier
2008
Abstract
A fast and simple procedure for designing relatively wide band fractional delay (FD) all-pass filters is proposed and filters designed based on it are compared to those designed using Thiran's method, which is one of the simplest, fastest and widely used approaches in designing FD all-pass filters. It is shown that filters designed using the introduced method have wider fractional group delay (fgpd) bandwidths compared to those obtained via Thiran's technique, as well as some other desired properties. The designed filters are also demonstrated to be stable for several pairs of filter orders and fgpd values. © 2007 Elsevier B.V. All rights reserved
Development of a Design Tool for Restaging of Centrifugal Compressors
, M.Sc. Thesis Sharif University of Technology ; Ghorbanian, kaveh (Supervisor)
Abstract
The purpose of this research is theoretical and numerical investigations on centrifugal compressor. A computer code has been developed to simulate single-zone and two-zone model, based on the revised formulation for real gas, using Peng-Robinson equations. Single-zone modeling, also known as meanline method, established based on 1-D equations of fluid dynamics considering ideal gas relations, empirical loss correlations, slip factors, impeller efficiency and no wake or separation regions. Considering usual significant separated regions in the gas path of impellers, two-zone (jet and wake zone) model has been developed to achieve a more reliable simulation by using fewer correlations based on...
Mathematical Problems of Sudoku Puzzle and their Relationship
, M.Sc. Thesis Sharif University of Technology ; Mahmoodian, Ebadollah (Supervisor)
Abstract
The Sudoku puzzle is played on a 9 × 9 grid which is divided into nine boxes each with 3 × 3 cells. Initially, some digits between 1 and 9 are given on the grid as the clues. Generalized Sudoku (a table of n2 by n2 that includes n2 blocks with n cells and in each of its rows, columns and blocks has all numbers from 1 to n2 appeared once and only once) can be considered too. Millions of people around the world are tackling one of the hardest problems in computer science without even knowing it. The first such puzzle appeared in the May 1979 edition of Dell P encil P uzzles and W ord Games and, according to research done by W ill Shortz, the crossword editor of the N ew Y ork T imes, was...
UCS-NT: An unbiased compressive sensing framework for Network Tomography
, Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings ; 2013 , Pages 4534-4538 ; 15206149 (ISSN) ; 9781479903566 (ISBN) ; Rabiee, H. R ; Hashemifar, Z. S ; Sharif University of Technology
2013
Abstract
This paper addresses the problem of recovering sparse link vectors with network topological constraints that is motivated by network inference and tomography applications. We propose a novel framework called UCS-NT in the context of compressive sensing for sparse recovery in networks. In order to efficiently recover sparse specification of link vectors, we construct a feasible measurement matrix using this framework through connected paths. It is theoretically shown that, only O(k log(n)) path measurements are sufficient for uniquely recovering any k-sparse link vector. Moreover, extensive simulations demonstrate that this framework would converge to an accurate solution for a wide class of...
Detection of top-K central nodes in social networks: A compressive sensing approach
, Article Proceedings of the 2015 IEEE/ACM International Conference on Advances in Social Networks Analysis and Mining, ASONAM 2015, 25 August 2015 through 28 August 2015 ; 2015 , Pages 902-909 ; 9781450338547 (ISBN) ; Pei, J ; Tang, J ; Silvestri, F ; Sharif University of Technology
Association for Computing Machinery, Inc
2015
Abstract
In analysing the structural organization of a social network, identifying important nodes has been a fundamental problem. The concept of network centrality deals with the assessment of the relative importance of a particular node within the network. Most of the traditional network centrality definitions have a high computational cost and require full knowledge of network topological structure. On the one hand, in many applications we are only interested in detecting the top-k central nodes of the network with the largest values considering a specific centrality metric. On the other hand, it is not feasible to efficiently identify central nodes in a large real-world social network via...
Compressed sensing in cyber physical social systems
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 10760 LNCS , 2018 , Pages 287-305 ; 03029743 (ISSN) ; Ghalebi, K. E ; Movaghar, A ; Mahyar, H ; Sharif University of Technology
2018
Abstract
We overview the main results in Compressed Sensing and Social Networks, and discuss the impact they have on Cyber Physical Social Systems (CPSS), which are currently emerging on top of the Internet of Things. Moreover, inspired by randomized Gossip Protocols, we introduce TopGossip, a new compressed-sensing algorithm for the prediction of the top-k most influential nodes in a social network. TopGossip is able to make this prediction by sampling only a relatively small portion of the social network, and without having any prior knowledge of the network structure itself, except for its set of nodes. Our experimental results on three well-known benchmarks, Facebook, Twitter, and Barabási,...
Lot sizing and job shop scheduling with compressible process times: A cut and branch approach
, Article Computers and Industrial Engineering ; Volume 85 , 2015 , Pages 196-205 ; 03608352 (ISSN) ; Modarres, M ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
This paper studies simultaneous lot sizing and scheduling problem in a job shop environment over a finite number of periods. The machines are flexible such that the production manager is able to change their working speeds. Also, the production schedule of the items over machines should be in consistence with technological precedence relationships. The problem is formulated as an integer linear program. Then, a number of valid inequalities are developed based on the problem structures. The proposed valid inequalities are added to the problem formulation in a "cut and branch" manner to accelerate the search process by common solvers. Finally, performance of the valid inequalities is...
Thermal stresses and kinetics of phase transformation on the run-out table after hot strip rolling of low-carbon steels
, Article International Journal of Advanced Manufacturing Technology ; Volume 83, Issue 9-12 , 2016 , Pages 1725-1736 ; 02683768 (ISSN) ; Serajzadeh, S ; Sharif University of Technology
2016
Abstract
A thermo-elastic analysis coupled with a phase change model is employed to evaluate thermal stresses as well as progress of austenite decomposition after hot strip rolling operations. The thermo-mechanical finite element analysis is utilized to assess the distributions of temperature and thermal stresses during cooling while at the same time, a model based on the additivity rule is used to determine the rate of austenite to ferrite decomposition. The proposed model is applicable to multi-pass rolling schedules while the effects of different process parameters including the rolling speed and cooling configuration of the run-out table can be taken into account. In order to verify the...