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    An introductory course on differentiable manifolds

    , Book Shashahani, Siavash
    Dover Publications, Inc  2016
    Based on author Siavash Shahshahani's extensive teaching experience, this volume presents a thorough, rigorous course on the theory of differentiable manifolds. Geared toward advanced undergraduates and graduate students in mathematics, the treatment's prerequisites include a strong background in undergraduate mathematics, including multivariable calculus, linear algebra, elementary abstract algebra, and point set topology. More than 200 exercises offer students ample opportunity to gauge their skills and gain additional insights.
    The four-part treatment begins with a single chapter devoted to the tensor algebra of linear spaces and their mappings. Part II brings in neighboring points to... 

    Solution of nonlinear fractional differential equations using homotopy analysis method

    , Article Applied Mathematical Modelling ; Volume 34, Issue 6 , 2010 , Pages 1634-1641 ; 0307904X (ISSN) Ganjiani, M ; Sharif University of Technology
    In this article, the homotopy analysis method has been applied to solve nonlinear differential equations of fractional order. The validity of this method has successfully been accomplished by applying it to find the solution of two nonlinear fractional equations. The results obtained by homotopy analysis method have been compared with those exact solutions. The results show that the solution of homotopy analysis method is good agreement with the exact solution. Crown  

    An improved truncated differential cryptanalysis of klein

    , Article Tatra Mountains Mathematical Publications ; Volume 67, Issue 1 , 2016 , Pages 135-147 ; 12103195 (ISSN) Rasoolzadeh, S ; Ahmadian, Z ; Salmasizadeh, M ; Aref, M. R ; Sharif University of Technology
    De Gruyter Open Ltd  2016
    KLEIN is a family of lightweight block ciphers which was proposed at RFIDSec 2011 by Gong et. al. It has three versions with 64, 80 or 96-bit key size, all with a 64-bit state size. It uses 16 identical 4-bit S-boxes combined with two AES's MixColumn transformations for each round. This approach allows compact implementations of KLEIN in both low-end software and hardware. Such an unconventional combination attracts the attention of cryptanalysts, and several security analyses have been published. The most successful one was presented at FSE 2014 which was a truncated differential attack. They could attack up to 12, 13 and 14 rounds out of total number of 12, 16 and 20 rounds for... 

    Oscillation of solutions of second-order nonlinear differential equations of Euler type

    , Article Journal of Mathematical Analysis and Applications ; Volume 326, Issue 2 , 2007 , Pages 1076-1089 ; 0022247X (ISSN) Aghajani, A ; Moradifam, A ; Sharif University of Technology
    We consider the nonlinear Euler differential equation t2 x″ + g (x) = 0. Here g (x) satisfies x g (x) > 0 for x ≠ 0, but is not assumed to be sublinear or superlinear. We present implicit necessary and sufficient condition for all nontrivial solutions of this system to be oscillatory or nonoscillatory. Also we prove that solutions of this system are all oscillatory or all nonoscillatory and cannot be both. We derive explicit conditions and improve the results presented in the previous literature. We extend our results to the extended equation t2 x″ + a (t) g (x) = 0. © 2006 Elsevier Inc. All rights reserved  

    Undamped oscillations in fractional-order Duffing oscillator

    , Article Signal Processing ; Volume 107 , February , 2015 , Pages 361-367 ; 01651684 (ISSN) Rostami, M ; Haeri, M ; Sharif University of Technology
    Elsevier  2015
    This paper studies undamped oscillations of fractional-order Duffing system. Stability theorems for fractional order systems are used to determine the characteristic polynomial of the system in order to find the parametric ranges for undamped oscillations in this system. We also derive relations for estimating the frequency and the amplitude of the oscillations in this system using a describing function method. Finally numerical simulation results are provided to justify the analysis  

    Control of vibration amplitude, frequency and damping of an electrostatically actuated microbeam using capacitive, inductive and resistive elements

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 12 November 2010 through 18 November 2010, Vancouver, BC ; Volume 10 , 2010 , Pages 263-270 ; 9780791844472 (ISBN) Pasharavesh, A ; Alizadeh Vaghasloo, Y ; Fallah, A ; Ahmadian, M. T ; Sharif University of Technology
    In this study vibration amplitude, frequency and damping of a microbeam is controlled using a RLC block containing a capacitor, resistor and inductor in series with the microbeam. Applying this method all of the considerable characteristics of the oscillatory system can be determined and controlled with no change in the geometrical and physical characteristics of the microbeam. Euler-Bernoulli assumptions are made for the microbeam and the electrical current through the microbeam is computed by considering the microbeam deflection and its voltage. Considering the RLC block, the voltage difference between the microbeam and the substrate is calculated. Two coupled nonlinear partial... 

    Statistical Cryptanalysis on MIBS as a Lightweight Algorithm

    , M.Sc. Thesis Sharif University of Technology Beheshtifard, Saeed (Author) ; Salmasizadeh, Mahmud (Supervisor) ; Mohajeri, Javad (Co-Advisor)
    In RFIDtags application or sensor network for some hardware constraints we can not use all-purpose crypto systems such as AES,DES.In this applications in trade off between security and efficiency considering inherent limitation،we desire to satisfy moderate level of security.In recent years various lightweight algorithm has been designed.Purpose of this thesis is cryptanalysis on MIBS as a lightweight algorithm.This lightweight block cipher with Feistel structure and data length of 64-bit uses key lengths of 64-bit or 80-bit and consists of 32 rounds.Methods of attacks are differential،impossible differential and differential fault.the results of differential and impossible differential... 

    Impossible differential cryptanalysis of Piccolo lightweight block cipher

    , Article 2014 11th International ISC Conference on Information Security and Cryptology, ISCISC 2014 ; Sep , 2014 , p. 89-94 Azimi, S. A ; Ahmadian, Z ; Mohajeri, J ; Aref, M. R ; Sharif University of Technology
    This paper analyzes the Piccolo family of lightweight block ciphers against the impossible differential cryptanalysis. A combination of some ploys such as decreasing the S-box computations, finding an appropriate propagation of differentials, utilizing hash tables and using the linearity of the key-schedule as well as disregarding subkeys of two rounds lead to 12-round and 13-round impossible differential attack on Piccolo-80 and 15-round attack on Piccolo-128. The time and data complexity of the attack against Piccolo-80 is 255.18 and 236.34 for 12-round and 269.7 and 243.25 for 13-round, respectively. Moreover, the time and data complexity for 15 rounds cryptanalysis of Piccolo-128 are... 

    Impossible differential cryptanalysis of reduced-round TEA and XTEA

    , Article 12th International ISC Conference on Information Security and Cryptology, 8 September 2015 through 10 September 2015 ; 2015 , Pages 58-63 ; 9781467376099 (ISBN) Hajari, M ; Azimi, S.A ; Aghdaie, P ; Salmasizadeh, M ; Aref, M. R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc 
    TEA and XTEA are two lightweight Feistel block ciphers, each of which has a block size of 64 bits and a key size of 128 bits. These two ciphers have ARX structure, i.e. their round functions consist of modular addition, shift and XOR to be exact. Since each operation of TEA and XTEA can be done in a bitwise fashion, we are able to use early abort technique in the impossible differential attack that helps us to remove inappropriate pairs as soon as possible, hence decreasing time complexity. In this paper we present two new 15-round impossible differential characteristics, resulting in the first known impossible differential cryptanalysis mounted on 19 rounds of TEA and 25 rounds of XTEA  

    New polysaccharide-g-polyacrylonitrile copolymers: synthesis and thermal characterization [electronic resource]

    , Article Polymers for Advanced Technologies ; Volume 14, Issue 7, pages 508–516, July 2003 Zohurian Mehr, M. J. (Mohammad Jalal) ; Pourjavadi, Ali ; Sharif University of Technology
    Various natural and modified polysaccharides (i.e. arabic gum, tragacanth gum, xanthan gum, sodium alginate, chitosan, sodium carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose) were modified using ceric-initiated graft polymerization of acrylonitrile under inert atmosphere. Grafting was confirmed using spectral (FT-IR) proofs. The grafting parameters were determined by conventional methods. Thermal characteristics of the homopolymer-free copolymers were studied using differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) under nitrogen atmosphere. The major thermal transitions as well as the activation energy of the major decomposition stages were... 

    Efficient modulation technique for optical code division multiple access networks: Differential pulse position modulation

    , Article IET Optoelectronics ; Vol. 8, issue. 5 , 2014 , p. 181-190 Khazraei, S ; Shoaie, M. A ; Pakravan, M. R ; Sharif University of Technology
    In this study, the authors study a fibre-optic local area network deploying optical code division multiple access technique with differential M-ary pulse position modulation (DPPM). The authors present the performance analysis of DPPM signalling using a double optical hardlimiter receiver structure considering the impairment caused by interference of other users. The analysis assumes a set of bit asynchronous transmitters employing generalised optical orthogonal codes for their DPPM signalling (GOOC-DPPM). Using mathematical analysis and simulations, the authors have demonstrated that GOOCDPPM improves both frame error probability and the maximum achievable network throughput compared with... 

    Far-field dynamic behavior of a half-space under an inertial strip foundation subjected to a time-harmonic force

    , Article Latin American Journal of Solids and Structures ; Volume 10, Issue 3 , 2013 , Pages 453-471 ; 16797817 (ISSN) Dehestani, M ; Malidarreh, N. R ; Choobbasti, A. J ; Vafai, A ; Sharif University of Technology
    Recent research works demonstrated that the interaction between the loads and the carrying structure's boundary which is related to the inertia of the load is an influential factor on the dynamic response of the structure. Although effects of the inertia in moving loads were considered in many works, very few papers can be found on the inertial effects of the stationary loads on structures. In this paper, an elastodynamic formulation was employed to investigate the dynamic response of a homogeneous isotropic elastic half-space under an inertial strip foundation subjected to a time-harmonic force. Fourier integral transformation was used to solve the system of Poisson-type partial... 

    Non-convex self-dual Lagrangians: New variational principles of symmetric boundary value problems

    , Article Journal of Functional Analysis ; Volume 260, Issue 9 , 2011 , Pages 2674-2715 ; 00221236 (ISSN) Moameni, A ; Sharif University of Technology
    We study the concept and the calculus of Non-convex self-dual (Nc-SD) Lagrangians and their derived vector fields which are associated to many partial differential equations and evolution systems. They indeed provide new representations and formulations for the superposition of convex functions and symmetric operators. They yield new variational resolutions for large class of Hamiltonian partial differential equations with variety of linear and nonlinear boundary conditions including many of the standard ones. This approach seems to offer several useful advantages: It associates to a boundary value problem several potential functions which can often be used with relative ease compared to... 

    A new approach for solving resource constrained project scheduling problems using differential evolution algorithm

    , Article International Journal of Industrial Engineering Computations ; Volume 7, Issue 2 , 2016 , Pages 205-216 ; 19232926 (ISSN) Eshraghi, A ; Sharif University of Technology
    Growing Science 
    One subcategory of project scheduling is the resource constrained project scheduling problem (RCPSP). The present study proposes a differential evolution algorithm for solving the RCPSP making a small change in the method to comply with the model. The RCPSP is intended to program a group of activities of minimal duration while considering precedence and resource constraints. The present study introduces a differential evolution algorithm and local search was added to improve the performance of the algorithm. The problems were then solved to evaluate the performance of the algorithm and the results are compared with genetic algorithm. Computational results confirm that the differential... 

    Impossible differential cryptanalysis of reduced-round midori64 block cipher

    , Article 2017 14th International ISC (Iranian Society of Cryptology) Conference on Information Security and Cryptology, ISCISC 2017, 6 September 2017 through 7 September 2017 ; 2018 , Pages 31-36 ; 9781538665602 (ISBN) Rezaei Shahmirzadi, A ; Azimi, S. A ; Salmasizadeh, M ; Mohajeri, J ; Aref, M. R ; Sharif University of Technology
    Impossible differential attack is a well-known mean to examine robustness of block ciphers. Using impossible differential cryptanalysis, we analyze security of a family of lightweight block ciphers, named Midori, that are designed considering low energy consumption. Midori state size can be either 64 bits for Midori64 or 128 bits for Midori128; however, both versions have key size equal to 128 bits.In this paper, we mainly study security of Midori64. To this end, we use various techniques such as early-abort, memory reallocation, miss-in-the-middle and turning to account the inadequate key schedule algorithm of Midori64. We first show two new 7-round impossible differential characteristics... 

    A universal formula for generalized cardinal B-splines

    , Article Applied and Computational Harmonic Analysis ; Volume 45, Issue 2 , 2018 , Pages 341-358 ; 10635203 (ISSN) Amini, A ; Madani, R ; Unser, M ; Sharif University of Technology
    Academic Press Inc  2018
    We introduce a universal and systematic way of defining a generalized B-spline based on a linear shift-invariant (LSI) operator L (a.k.a. Fourier multiplier). The generic form of the B-spline is βL=LdL−1δ where L−1δ is the Green's function of L and where Ld is the discretized version of the operator that has the smallest-possible null space. The cornerstone of our approach is a main construction of Ld in the form of an infinite product that is motivated by Weierstrass’ factorization of entire functions. We show that the resulting Fourier-domain expression is compatible with the construction of all known B-splines. In the special case where L is the derivative operator (linked with... 

    Cost-based differential pricing for a make-to-order production system in a competitive segmented market

    , Article Journal of Revenue and Pricing Management ; Volume 19, Issue 4 , 2020 , Pages 266-275 Teimoury, E ; Modarres, M ; Neishaboori, M ; Sharif University of Technology
    Palgrave Macmillan  2020
    Optimal queuing system design includes deciding about some variables such as location, capacity, price, and delivery time. In order to develop an optimized system, it is essential to solve the optimization problem for all the decision variables simultaneously. In this paper, a make-to-order system is considered. In this system, some facilities are developed in different points. According to the make-to-order system definition, these facilities keep no inventory from final product. Orders are received from customers and the requested products are assembled. Due to existence of some differences among customers, they are divided into two distinct categories including express and regular... 

    Impossible differential cryptanalysis of safer++

    , Article 2008 International Conference on Security and Management, SAM 2008, Las Vegas, NV, 14 July 2008 through 17 July 2008 ; July , 2008 , Pages 10-14 ; 160132085X (ISBN); 9781601320858 (ISBN) Bahrak, B ; Eghlidos, T ; Aref, M. R ; Sharif University of Technology
    In this paper, we describe an impossible differential property for 2.5 rounds of Safer++. It allows an impossible differential attack on 4 rounds of Safer++. The proposed attack requires 2 23 chosen plaintexts and 2 75 bytes of memory and performs 2 84 4-round Safer++ encryptions. The method developed to attack Safer++ can be applied to other block ciphers in Safer family. 1  

    Study of thermal behavior of α-PbO2, using TG and DSC

    , Article Journal of Thermal Analysis and Calorimetry ; Volume 92, Issue 3 , 2008 , Pages 917-920 ; 13886150 (ISSN) Sajadi, S. A. A ; Alamolhoda, A. A ; Hashemian, S. J ; Sharif University of Technology
    Using two techniques of thermogravimetry and differential scanning calorimetry under O2 gas atmosphere from 25 to 600°C, the thermal behavior of laboratory-produced compound lead(IV) oxide α-PbO2 was investigated. The identity of products at different stages were confirmed by XRD technique. Both techniques produced similar results supporting the same decomposition stages for the compound. Three distinct energy changes were observed, namely, two endothermic and one exothermic in DSC. The amount of ΔH for each peak is also reported. © 2008 Springer Science+Business Media, LLC  

    Differential pulse voltammetric determination of propylthiouracil and methylthiouracil using their catalytic effects on the electrochemical oxidation of catechol

    , Article International Journal of Electrochemical Science ; Volume 2, Issue 2 , 2007 , Pages 158-168 ; 14523981 (ISSN) Shahrokhian, S ; Saberi, R. S ; Sharif University of Technology
    The electrochemical behavior of catechol in the presence of propylthiouracil (PTU) and methylthiouracil (MTU) at a glassy carbon electrode is thoroughly investigated. The cyclic voltammetric studies of the systems are performed in different pHs and sweep rates. The results of the voltammetric foundations show an electrocatalytic oxidation of catechol in the presence of PTU and MTU, leading to a remarkable increase in the anodic peak current of catechol together with the contemporaneous disappearance of the corresponding cathodic wave. The presented mechanism shows the nucleophilic addition/reduction of the electro-generated o-quinone by the PTU or MTU, which produced chemically reduced...