Loading...
Search for:
nateghi--morteza
0.132 seconds
Total 202 records
Combination Services in A Cloud Manufacturing System With Regard to Quality as A Fuzzy Criteria
, M.Sc. Thesis Sharif University of Technology ; Hooshmand, Mahmoud (Supervisor)
Abstract
Today, due to the development of information technology and fierce competition among manufacturers, the need to reduce the production costs and increase the variety are strongly felt. Each process in the cloud manufacturing is first considered as a service product development, and then, specializing each of these services, provides us a lower cost, along with a higher accuracy, and quality.The modern world is the world full of uncertainty. The uncertainty, which causes the manufacturers to develop products that consume a large quantity of, fixed costs. That is why utilizing such a perspective can reduce investment risk in a new product development. Combining the production services by...
UWB Channel Modeling Using Time-Domain Ray Tracing
, M.Sc. Thesis Sharif University of Technology ; Shishegar, Amir Ahmad (Supervisor)
Abstract
Nowadays, wireless communication plays a key role in everyday lives and has many different applications. Today’s communication systems require high bandwidths in order to transfer data with higher bitrates. Among these, modeling a wireless channel is one of the most important challenges in wireless communications. Modeling an indoor Ultra-Wide-Band (UWB) wireless channel has been involved in a great number of researches. In order to model a UWB channel, we need to correctly investigate electromagnetic waves inside the buildings. Amongst different methods that are used for this aim, ray tracing method is one of the most accurate and fast ones. In this thesis, time-domain reflection and...
Response-only modal identification of structures using limited sensors
, Article Structural Control and Health Monitoring ; Volume 20, Issue 6 , 2013 , Pages 987-1006 ; 15452255 (ISSN) ; Ghahari, S. F ; Nateghi, F ; Taciroglu, E ; Sharif University of Technology
2013
Abstract
Herein, we propose a method based on the existing second-order blind identification of underdetermined mixtures technique for identifying the modal characteristics - namely, natural frequencies, damping ratio, and real-valued partial mode shapes of all contributing modes - of structures with a limited number of sensors from recorded free/ambient vibration data. In the second-order blind identification approach, second-order statistics of recorded signals are used to recover modal coordinates and mode shapes. Conventional versions of this approach require the number of sensors to be equal to or greater than the number of active modes. In the present study, we first employ a parallel factor...
Estimation of Bank Loan Interest Rate and Determining its Correlated Factors: A Case Study of Listed Companies in Iran
, M.Sc. Thesis Sharif University of Technology ; Madanizadeh, Ali (Supervisor) ; Mahmoodzadeh, Amineh (Supervisor)
Abstract
Bank loans are one of the main sources of financing for enterprises and the most important source of financing for large enterprises in Iran. Uncertainty about future conditions and asymmetric information between the bank and the firm puts the provision of loans at risk. According to the principle of proportionality of risk and return, the interest rate of bank facilities should be proportional to the risk that the bank incurs in return for granting the loan. In general, the interest rate of bank loans can be affected by three types of risks: the credit risk of the applicant firm, the risk of the lender bank and the macroeconomic environment risk. In this study, we try to estimate the...
Ant colony algorithm for the shortest loop design problem [electronic resource]
, Article Computers and Industrial Engineering, Elsevier ; Volume 50, Issue 4, August 2006, Pages 358–366 ; Kazemi, Morteza ; Sharif University of Technology
Abstract
In this paper, a new algorithm for solving the shortest loop design problem is presented. The shortest loop design problem is to find the shortest loop for an automated guided vehicle covering at least one edge of each department of a block layout. In this paper, first it is shown that this problem can be represented as a graph model. The properties of the presented model enable us to design a meta-heuristic based on ant colony system algorithm for solving the shortest loop design problem. Computational results show the efficiency of our algorithm in compare to the other techniques
Radiation and convection heat transfer optimization with MHD analysis of a hybrid nanofluid within a wavy porous enclosure
, Article Journal of Magnetism and Magnetic Materials ; Volume 566 , 2023 ; 03048853 (ISSN) ; Erfani Moghaddam, M. A ; Nateghi, S ; Behshad Shafii, M ; Ganji, D. D ; Sharif University of Technology
Elsevier B.V
2023
Abstract
Thermal performance maximization is a necessity in various systems that are dealing with any scale of heat flux. This requirement has been intensified due to introduction of more complex and highly crammed products, making heat dissipation a daunting task. Addressing this challenge, a curved porous star-shaped enclosure with a rounded cavity and occupied by hybrid nanoparticles of Fe3O4-Al2O3 scattered uniformly in 1-Hexanol has been simulated by Galerkin finite element method. The temperature difference between inner cavity and outer wavy surface stirred the heat flux within the bounded domain. The determinants of thermal evolution are classified by porosity alteration, radiation intensity,...
Bacterial biopolymers in tissue engineering and regenerative medicine; current applications and future perspective
, Article Biocatalysis and Agricultural Biotechnology ; Volume 54 , 2023 ; 18788181 (ISSN) ; Mohammadipanah, F ; Sadat Mirtaleb, M ; Maddah Gazani, M ; Nateghi, S ; Abbasi, P ; Sharif University of Technology
Elsevier Ltd
2023
Abstract
Tissue engineering (TE), a fast-growing field of regenerative medicine, has been designed to replace diseased or damaged tissues. As cellular factories, microbes produce a wide range of intracellular and extracellular biopolymers using energy resources. Bacterial biopolymers play an essential role in the competition of microorganisms with competitors. With the detailed knowledge of these bacterial metabolites, extensive applications have been provided in the medicine, food, and drug industry. Bacterial biopolymers, including polysaccharides, polyamides, polyphosphates, polyesters, and enzymes, with vast diversity and desirable properties, are the most frequently used products in TE. Herein...
Modeling Reaction and Distribution of Water in Nanopores of the Cathode Catalyst Layer of PEM Fuel Cell
, M.Sc. Thesis Sharif University of Technology ; baghalha, morteza (Supervisor)
Abstract
In the proton exchange membrane fuel cells (PEM, the produced water would be divided into two phases of vapor and liquid. distribution of both liquid and vapor phases in different cell layers affects the performance, the efficiency and the life of a fuel cell significantly. Moreover, Nano pores of the cathode catalyst layer are involved with some phenomena such as electrochemical reaction kinetics, heat and mass transfer and interface phase change. One of the most important problems in the performance of fuel cells is distribution of liquid water in the porous areas. Water flooding in fuel cells causes to delay in oxygen transport to active sites in the catalyst layer because the pores of...
Love Wave Propagation in a Functionally Graded Magneto-Electro-Elastic Half-Space with Quadratic Variations
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
The propagation behavior of Love wave in functionally graded magneto-electro-elastic half-spaces with a quadratic variation is addressed. The magneto-electromechanical coupling factor, the dispersion relations, electric potential, magnetic potential and displacement are obtained analytically for both magneto-electrically open and short conditions. The effect of gradient coefficient on phase velocity, group velocity and magneto-electromechanical coupling factor are plotted and discussed. Research on the wave propagation in magneto-electro-elastic materials is still very limited. This work provides us with a theoretical foundation to design and practically apply SAW devices with high...
Elastic Analysis of a Surface Stiffened Transversely Isotropic Half-space Under a Buried Horizontal Point Load
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
In this study, the interaction between thin plate completely bonded to the transversely isotropic halfspace and a concentrated force applied horizontally (Mindlin-type force) are considered. This problem has been solved analytically. This problem is used as sample for thin solid films and surface coating technology, where the surface of solid is covered by thethin plate for increasing its stiffness. Moreover, this problem is a good sample when homogenous solid is subjected to contact loading and can be seen that mechanical properties of material which is near the solid surface varies; consequently, a two-phase solid is created.Because of the influence of noted inhomogeneity, solid is...
Modeling and Simulation of the Catalyst Regeneration Process of FCC Unit of Abadan Refinery
, M.Sc. Thesis Sharif University of Technology ; Baghalha, Morteza (Supervisor)
Abstract
Hydrodynamics plays a crucial role in defining the performance of fluidized beds. The numerical simulation of fluidized bed is very important in the prediction of its behaviour. From this point of view, in the present study a dynamic two dimensioanl model is developed for the modeling of regenerator system of a UOP fluid catalytic cracking (FCC) unit of Abadan refinery with a high-efficiency regenerator. Of the various modeling and simulation techniques, computational fluid dynamics (CFD) is employed in this thesis. Effects of gas velocity, the transient local solid volume fraction, pressure drop for gas and solid phase, solid holdup distribution and solid circulation pattern have been...
Secure- multiparty Computation Protocol for Privacy Preserving Data Mining
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
Privacy preserving data mining helps organizations and companies not only to deal with privacy concerns of customers and regular limitations, but also to benefit from collaborative data mining. Utilizing cryptographic techniques and secure multiparty computation (SMC) are among widely employed approaches for preserving privacy in distributed data mining. The general purpose of secure multiparty computation protocols to compute specific functions on private inputs of parties in a collaborative manner and without revealing their private inputs. Providing rigorous security proof of secure multiparty computation makes it a good choice for privacy preservation, despite of its cryptographic...
Information-flow Analysis in Android Apps for Protecting User Privacy
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
The rapid growth of Android operating system alongside its open-source nature has made it as the most popular operating system of mobile devices. On the other hand, regarding the increasing computational power of mobile devices, a wide variety of applications are coming to this type of devices. Meanwhile unfortunately many malicious softwares trying to keep up with other applications, are targeting this popular operating system. Therefore with regard to the fact that this type of devices usually store private and sensitive information of their users, security of mobile operating systems is considered very important. Having this matter in mind, the goal of this research work has been...
Analysis of Slabs Stiffened by Cables and Pedestals
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
In this study, a new concrete slab stiffened by concrete pedestals and steel cables is introduced. The slab system is studied by employing both analytical and numerical methods. The steel cables are connected to the edges of slab and the concrete pedestals mounted at the bottom face of slab act as the middle supports of cables. The tension force in the cable and its inclination results in upward forces acting at the bottom face of slab. With the aims of classical theory of thin plates and the superposition technique, the problem of a simply supported rectangular slab stiffened by cables is studied analytically. The obtained results are verified by a numerical modelling implemented in SAP2000...
Parametric Study of Telescopic Metallic Yielding Dampers
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
The parametric study of a new introduced metallic yielding damper called telescopic damper is addressed. The telescopic damper comprises of three concentric steel pipes connected together by lead shear keys. The inner and outer steel pipes are subjected to axial loading which results in the shear yielding of the embedded lead cylinders. The inner steel pipe has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Employing ABAQUS software, the behavior of damper under cyclic loading is studied numerically. The finite element model is verified by available results in the literature. The effects of inner and outer steel pipes thickness,...
An Access Control System for Time Series Data in NoSQL Databases
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
An important class of applications which have been rapidly growing recently is the one that create and use time series data. These types of data sets are ordered based on the timestamps associated to their data items. In practice, traditional relational databases are unable to satisfy the requirements of these data sets; however, NoSQL databases with column-wide data structure are appropriate infrastructure for them. These databases are very efficient in read and write operations (especially for time series data, which are ordered) and are able to store unstructured data. Time series data may contain valuable and sensitive information; hence, they should be protected from the information...
Database Schema Extraction Prevention Through DBMS Error Handling
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
Nowadays large volume of sensitive data of organizations are stored in the databases. Thus, databases are attractive to the attackers to execute different types of attacks with different purposes. The useful information that attackers try to achieve in the preliminary steps of the attacks against the databases, is the database structure or schema. One of the popular approach to extract the schema of a database is to analyze the returned error messages from its DBMS. Hence, a solution to prevent schema disclosure via the error messages is customizing and modifying them. To achieve this goal, in this thesis, we propose a framework to handle and customize the error messages automatically and...
Numerical Simulation of a Telescopic Metallic Yielding Damper
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
In this study, a new type of metallic yielding damper called Telescopic damper is proposed and analyzed numerically. The damper comprises of three concentric steel tubes connected together by lead shear keys. The relative axial deformation of steel tubes under axial forces results in shear deformation and yielding in lead shear keys and dissipates energy. The inner steel tube has a lock which limits its movement to some certain extent and beyond this limit the outer tube activates. Therefore, a multi-linear force-deformation behavior with two different yield plateaus is expected for the introduced telescopic damper. The multi-level yield plateaus of damper makes it effective in both low and...
Privacy Preserving Access Control for Service Composition in Cloud Computing
, M.Sc. Thesis Sharif University of Technology ; Amini, Morteza (Supervisor)
Abstract
Cloud computing is a new computing environment where computing infrastructure, platform and software are provided as a service. Rapid growth of cloud environments has increased the importance of security requirements and challenges for both service providers and users in cloud. Two main security issues in software as a service (SaaS) delivery model are access control and privacy preserving in basic web services and also in composite services obtaining through the automatic composition and inference of policies from the ones specified for basic services. In this thesis, we present a privacy preserving access control model and framework for service composition in SaaS delivery model of cloud...
Static and Dynamic Analysis of Nano Beams based on Second Strain Gradient Theory
, M.Sc. Thesis Sharif University of Technology ; Eskandari, Morteza (Supervisor)
Abstract
In this thesis, static and dynamic analysis of nano beams based on second strain gradient theory is presented. Due to their small sizes, nano electro mechanical devices (NEMS) hold tremendous promise for novel, versatile and very sensitive devices for different applications ranging from actuators, transducers and also mass, force, light and frequency detectors. Therefore accurate modeling and analysis of such devices has an important role in their design and performance improvement. Neglecting the size effect, traditional theory of elasticity can not be suitable to predict mechanical behavior of these systems and so, it should be used non-classical theories which include size dependency...