Almost every n -vertex graph is determined by Its 3 log 2 n -vertex subgraphs

, Article International Journal of Foundations of Computer Science ; Volume 31, Issue 5 , 2020 , Pages 611-619 Farhadian, A ; Sharif University of Technology

World Scientific 2020

Abstract

This paper proves that almost every n-vertex graph has the property that the multiset of its induced subgraphs on 3log2n vertices is sufficient to determine it up to isomorphism. That is, the probability that there exists two n-vertex graphs with the same multiset of 3log2n-vertex induced subgraphs goes to zero as n goes to infinity. © 2020 World Scientific Publishing Company

On Graph Reconstruction Conjecture

, M.Sc. Thesis Sharif University of Technology Farhadian, Ameneh (Author) ; Mahmoudian, Ebadollah (Supervisor)

Abstract

The reconstruction conjecture is an open and interesting problem that attracts some reserchers. Although some work toward this problem has been done; but no one have been able to solve it comlpetely. In this thesis, some new theorms are developed which extend the domain of reconstructible graphs. Also, a generalization of graph spectrum -called Alpha Spectrum- is introduced that is very effective in recognization of graphs

Efficient method for simplifying and approximating the S-boxes based on power functions

, Article IET Information Security ; Volume 3, Issue 3 , 2009 , Pages 114-118 ; 17518709 (ISSN) Farhadian, A ; Aref, M. R ; Sharif University of Technology

2009

Abstract

In recently proposed cipher algorithms, power functions over finite fields and specially inversion functions play an important role in the S-box design structure. In this study, a new systematic efficient method is introduced to cryptanalyse (to simplify and approximate) such S-boxes. This method is very simple and does not need any heuristic attempt and can be considered as a quick criterion to find some simple approximations. Using this new method, some approximations can be obtained for advanced encryption standard (AES) like S-boxes, such as AES, Camellia, Shark and so on. Finally as an application of this method, a simple linear approximation for AES S-box is presented. © The...

Structural Representation of Graphs

, Ph.D. Dissertation Sharif University of Technology Farhadian, Ameneh (Author) ; Fanai, Hamid Reza (Supervisor)

Abstract

In this thesis, we have shown that unique subgraphs of a graph have a key role in structure of the graph. Using unique subgraph which is called “anchor” here, the reconstruction of graphs is explained. Using anchor, we have shown that almost every n-vertex graph is determined by its 3log(n)-vertex subgraphs. In the second part of the thesis, a novel randomized algorithm is proposed for the graph isomorphism problem which is very simple and fast. It solves this problem with running time O(n^{2.373} \log(n)) for any pair of $n$-vertex graphs whose adjacency matrices are not strongly co-det. Strongly co-det pair of matrices have very special symmetric structure which can be disarranged to be...

Treatment of beet sugar wastewater by UAFB bioprocess

, Article Bioresource Technology ; Volume 98, Issue 16 , 2007 , Pages 3080-3083 ; 09608524 (ISSN) Farhadian, M ; Borghei, M ; Umrania, V. V ; Sharif University of Technology

2007

Abstract

The aim of this work was to study the treatment of strong beet sugar wastewater by an upflow anaerobic fixed bed (UAFB) at pilot plant scale. Three fixed bed bioreactors (each 60 L) were filled with standard industrial packing, inoculated with anaerobic culture (chicken manure, cow manure, anaerobic sludge digested from domestic wastewater) and operated at 32-34 °C with 20 h hydraulic retention time (HRT) and influent COD ranging between 2000-8000 mg/L. Under these conditions the maximum efficiency of organic content reduction in the reactor ranged from 75% to 93%. The reactor filled with standard pall rings made of polypropylene with an effective surface area of 206 m2/m3 performed best in...

Kinetics and Mechanism of the Reduction of Hexavalent Chromium to Less Toxic Materials on ZnO Nanostructured Surfaces: the Effect of Wavelength and Light Intensity on the Reaction Rate

, M.Sc. Thesis Sharif University of Technology Alyannezhadi, Mojtaba (Author) ; Moshfegh, Alireza (Supervisor) ; Naseri, Ameneh (Supervisor)

Abstract

Hexavalent chromium ion (Cr+6) is a very toxic type of heavy metal in industrial effluents which is not biodegradable and accumulates in the human body that can cause genetic mutations and cancer. The aim of this project is to investigate the effect of wavelength and intensity of appropriate light on the reaction rate of photocatalytic reduction of Cr+6 ion to less toxic materials. In this project, we first designed and constructed a photocatalytic reactor to investigate the effect of wavelength and intensity of incident light on the reaction rate. The home-made photocatalytic reactor consisted of 120 LEDs in 12 different wavelengths, which has ability to control the intensity and...