Fault Modeling of Transient Faults in Embedded Processors

, M.Sc. Thesis Sharif University of Technology Tajik, Hossein (Author) ; Ejlali, Alireza (Supervisor)

Abstract

Many embedded processors are used in harsh environments and their behavior should be investigated against the incidence of common faults. Fault Injection is a prevalent method to do this investigation. Simulation-based fault injection is one of the most prominent forms of fault injection. A fault model is required to do simulation-based fault injection. Simulated faults should have the most similarity to the real faults. Temperature variation and in the extreme case thermal shock is one of the probable faults in harsh environment. In this thesis, we want to propose fault models for thermal shock in various abstraction levels, evaluate and compare these fault models and present methods to use...

DC to 40-GHz compact single-layer crossover

, Article IEEE Microwave and Wireless Components Letters ; Volume 28, Issue 8 , 2018 , Pages 642-644 ; 15311309 (ISSN) Tajik, A ; Fakharzadeh, M ; Mehrany, K ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2018

Abstract

In this letter, a compact, wideband, and fully planar microstrip crossover structure is proposed. This design is based on a compact microstrip to coplanar waveguide transition, which has a measured bandwidth extending from dc to 40 GHz. At 20 GHz, the measured insertion loss, return loss, and isolation are better than 0.35, 21, and 19 dB, respectively. This circuit is ultracompact with the core size of 3 mm ×3 mm, which is 0.2λ×0.2 λ at 20 GHz. © 2012 IEEE

Factors Explaining the Intention of Iranian Apparel Smes to Initiate Export and Internationalization

, M.Sc. Thesis Sharif University of Technology Tajik, Mohammad Hossein (Author) ; Kiamehr, Mahdi (Supervisor)

Abstract

Researches on internationalization and export have categorized all factors as internal and external and most of them try to explain this behavior by studying external factors. Recent study in this field have shown that simply promoting specific behavior is not enough, and it is important to try to change the attitudes of managers toward internationalization. Utilizing Theory of Planned Behavior (TPB), this research tries to understand the relationship between attitudes of managers and internationalization behavior of an organization. the explicit objective of this research is to determine the factors which influence the organization behavior on internationalization (specifically indirect...

Asymmetrical 4×4 butler matrix and its application for single layer 8×8 butler matrix

, Article IEEE Transactions on Antennas and Propagation ; Volume 67, Issue 8 , 2019 , Pages 5372-5379 ; 0018926X (ISSN) Tajik, A ; Shafiei Alavijeh, A ; Fakharzadeh, M ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2019

Abstract

The design procedure and measured results of a novel 4 × 4 Butler matrix are presented in this paper. This asymmetrical structure provides fairly flexible phase outputs; therefore, the array radiation pattern can be rotated around the array normal axis. The structure of this modified Butler matrix is discussed in detail, and the explicit design formulas are derived to achieve the arbitrary main beams direction. Using the proposed design procedure, the Butler matrix can provide even broadside and endfire beams. In addition, this structure is employed to design two Butler matrices, which generate similar patterns as a conventional 8 × 8 Butler matrix, using only single layer circuits with...

Dual Band Millimeter Wave Butler Matrix Design for 5G Mobile Communication using CRLH

, M.Sc. Thesis Sharif University of Technology Tajik, Ali (Author) ; Mehrany, Khashayar (Supervisor) ; Fakharzadeh, Mohammad (Co-Supervisor)

Abstract

In this thesis, study of some kinds of dual band transmission lines and structures are investigated. Attention to 3 important kinds, CRLH, SCRLH and the equal phase line are introduced and the formulations of each one are derived and considered. Also the method of designing these lines are attached. These lines form a complete category that makes the ability of designing all kind of dual band line with arbitrary frequencies and result phases with arbitrary non-integer ratio less or more than 1. Also an important attention is paid for the designing these lines in the microstrip configuration. Various kinds of Dual band structures are proposed at the last part of the introducing each lines....

Design and Prototype Fabrication of a Palm Tree Climbing Robot for Pruning and Picking Crops

, M.Sc. Thesis Sharif University of Technology Hatami Tajik, Mohammad Javad (Author) ; Alasty, Aria (Supervisor)

Abstract

Considering the importance of maintaining palm trees, this research focuses on the design of a climbing robot utilizing wheels. The goals of this robot include easy installation on the tree, climbing despite variations in trunk diameter and surface irregularities, maintaining static balance to prevent falling in a stationary state, and enabling tree pruning. Additionally, descending from the tree is an essential capability of this robot. For climbing, a rotating wheel and four auxiliary wheels are employed. A motor with a gearbox drives the rotating wheel, while the auxiliary wheels, supported by spring-lock mechanisms, provide the necessary force to prevent slipping and ensure stable...

Simple, Cost-effective, and continuous 3D dielectrophoretic microchip for concentration and separation of bioparticles

, Article Industrial and Engineering Chemistry Research ; Volume 59, Issue 9 , 2020 , Pages 3772-3783 Tajik, P ; Saidi, M. S ; Kashaninejad, N ; Nguyen, N. T ; Sharif University of Technology

American Chemical Society 2020

Abstract

Dielectrophoresis is a robust approach for manipulating bioparticles in microfluidic devices. In recent years, many groups have developed dielectrophoresis-based microfluidic systems for separation and concentration of various types of bioparticles, where the gradient of the electric field causes dielectrophoresis force acting on the suspended particles. Enhancing the gradient of the electric field with three-dimensional (3D) electrodes can significantly improve the efficiency of the system. Implementing planar electrodes in a 3D arrangement is a simple option to form a 3D-electrode configuration. This paper reports the development of a novel dielectrophoretic microfluidic system for...

Design and Fabrication of a Microfluidic Chip for Live and Dead Cell Separation

, M.Sc. Thesis Sharif University of Technology Tajik, Parham (Author) ; Firouzbakhsh, Keykhosrow (Supervisor) ; Saeedi, Mohammad Saeed (Supervisor)

Abstract

The recent breakthroughs in the lab-on-a-chip technology will not be directly used as clinical devices unless the specific applications are carefully tested and certified. As there is a growing trend towards microfluidic devices for biomedical research, an active microfluidic device was developed. Common microfabrication methods were used to develop a microchip to separate and concentrate live and dead cells based on the dielectrophoresis phenomenon. Unique capabilities of the dielectrophoresis phenomenon make it a powerful tool for micro particle manipulation in micro scale. In this research, geometry for the mentioned purpose is designed and optimized. Three-dimensional microelectrodes are...

Expand the shares together: envy-free mechanisms with a small number of cuts

, Article Algorithmica ; 2018 ; 01784617 (ISSN) Seddighin, M ; Farhadi, M ; Ghodsi, M ; Alijani, R ; Tajik, A. S ; Sharif University of Technology

Springer New York LLC 2018

Abstract

We study the problem of fair division of a heterogeneous resource among strategic players. Given a divisible heterogeneous cake, we wish to divide the cake among n players to meet these conditions: (I) every player (weakly) prefers his allocated cake to any other player’s share (such notion is known as envy-freeness), (II) the allocation is dominant strategy-proof (truthful) (III) the number of cuts made on the cake is small. We provide methods for dividing the cake under different assumptions on the valuation functions of the players. First, we suppose that the valuation function of every player is a single interval with a special property, namely ordering property. For this case, we...

Expand the shares together: envy-free mechanisms with a small number of cuts

, Article Algorithmica ; Volume 81, Issue 4 , 2019 , Pages 1728-1755 ; 01784617 (ISSN) Seddighin, M ; Farhadi, M ; Ghodsi, M ; Alijani, R ; Tajik, A. S ; Sharif University of Technology

Springer New York LLC 2019

Abstract

We study the problem of fair division of a heterogeneous resource among strategic players. Given a divisible heterogeneous cake, we wish to divide the cake among n players to meet these conditions: (I) every player (weakly) prefers his allocated cake to any other player’s share (such notion is known as envy-freeness), (II) the allocation is dominant strategy-proof (truthful) (III) the number of cuts made on the cake is small. We provide methods for dividing the cake under different assumptions on the valuation functions of the players. First, we suppose that the valuation function of every player is a single interval with a special property, namely ordering property. For this case, we...

A novel noise immune, Fuzzy approach to speaker independent, isolated word speech recognition

, Article 2006 World Automation Congress, WAC'06, Budapest, 24 June 2006 through 26 June 2006 ; 2006 ; 1889335339 (ISBN); 9781889335339 (ISBN) Halavati, R ; Shouraki, S. B ; Razaghpour, M ; Tajik, H ; Cholakian, A ; Sharif University of Technology

IEEE Computer Society 2006

Abstract

This paper presents a novel approach to isolated word speech recognition using fuzzy modeling which is specifically designed to ignore noise. The task is based on conversion of speech spectrogram into a linguistic fuzzy description and comparison of this representation with fuzzy linguistic descriptions of words. The method is tested on single speaker and multiple speaker tests and the results are compared with a widely used speech recognition approach, showing much higher noise resistance. Copyright - World Automation Congress (WAC) 2006

A novel approach to very fast and noise robust, isolated word speech recognition

, Article 18th International Conference on Pattern Recognition, ICPR 2006, Hong Kong, 20 August 2006 through 24 August 2006 ; Volume 3 , 2006 , Pages 190-193 ; 10514651 (ISSN); 0769525210 (ISBN); 9780769525211 (ISBN) Halavati, R ; Bagheri Shouraki, S ; Tajik, H ; Cholakian, A ; Razaghpour, M ; Sharif University of Technology

2006

Abstract

A novel very light weight approach to isolated word speech recognition is introduced. The approach uses a new simplistic feature set and a neural network recognition system. The algorithm's main processing requirements are FFT computation and a simple neural network comparison, making the method a suitable solution for low price embedded devices. The proposed method is tested on single speaker and multiple speaker test sets and the results are compared with a widely used speech recognition approach, presenting very fast recognition and quite good recognition rate. © 2006 IEEE

Envy-free mechanisms with minimum number of cuts

, Article 31st AAAI Conference on Artificial Intelligence, AAAI 2017, 4 February 2017 through 10 February 2017 ; 2017 , Pages 312-318 Alijani, R ; Farhadi, M ; Ghodsi, M ; Seddighin, M ; Tajik, A. S ; Amazon; Artificial Intelligence; Baidu; et al.; IBM; Tencent ; Sharif University of Technology

AAAI press 2017

Abstract

We study the problem of fair division of a heterogeneous resource among strategic players. Given a divisible heterogeneous cake, we wish to divide the cake among n players in a way that meets the following criteria: (I) every player (weakly) prefers his allocated cake to any other player's share (such notion is known as envy-freeness), (II) the mechanism is strategy-proof (truthful), and (III) the number of cuts made on the cake is minimal. We provide methods, namely expansion process and expansion process with unlocking, for dividing the cake under different assumptions on the valuation functions of the players. Copyright © 2017, Association for the Advancement of Artificial Intelligence...

Secrecy capacity scaling in large cooperative wireless networks

, Article IEEE Transactions on Information Theory ; Volume 63, Issue 3 , 2017 , Pages 1923-1939 ; 00189448 (ISSN) Mirmohseni, M ; Papadimitratos, P. P ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2017

Abstract

We investigate large wireless networks subject to security constraints. In contrast to point-to-point, interferencelimited communications considered in prior works, we propose active cooperative relaying-based schemes. We consider a network with nl legitimate nodes, ne eavesdroppers, and path loss exponent α ≥ 2. As long as n2e (log(ne))γ = o(nl ), for some positive γ , we show that one can obtain unbounded secure aggregate rate. This means zero-cost secure communication, given fixed total power constraint for the entire network. We achieve this result through: 1) the source using Wyner randomized encoder and a serial (multi-stage) block Markov scheme, to cooperate with the relays and 2) the...

Fast estimation of connectivity in fractured reservoirs using percolation theory

, Article SPE Journal ; Volume 12, Issue 2 , 2007 , Pages 167-178 ; 1086055X (ISSN) Masihi, M ; King, P. R ; Nuratza, P ; Sharif University of Technology

Society of Petroleum Engineers (SPE) 2007

Abstract

Investigating the impact of geological uncertainty (i.e., spatial distribution of fractures) on reservoir performance may aid management decisions. The conventional approach to address this is to build a number of possible reservoir models, upscale them, and then run flow simulations. The problem with this approach is that it is computationally very expensive. In this study, we use another approach based on the permeability contrasts that control the flow, called percolation approach. This assumes that the permeability disorder of a rock can be simplified to either permeable or impermeable. The advantage is that by using some universal laws from percolation theory, the effect of the complex...

A new decoding scheme for errorless codes for overloaded CDMA with active user detection

, Article 2011 18th International Conference on Telecommunications, ICT 2011, Ayia Napa, 8 May 2011 through 11 May 2011 ; 2011 , Pages 201-205 ; 9781457700248 (ISBN) Mousavi, A ; Pad, P ; Delgosha, P ; Marvasti, F ; Sharif University of Technology

2011

Abstract

Recently, a new class of binary codes for overloaded CDMA systems are proposed that not only has the ability of errorless communication but also suitable for detecting active users. These codes are called COWDA. In [1], a Maximum Likelihood (ML) decoder is proposed for this class of codes. Although the proposed scheme for coding/decoding shows impressive performance, the decoder can be significantly improved. In this paper, by assuming practical conditions for the traffic in the system, we suggest and prove an algorithm that increases the performance of the decoder several orders of magnitude (the Bit-Error-Rate (BER) is divided by a factor of about 400 in some E b/N0's). The algorithm...

Estimation of the Effective Permeability of Heterogeneous Porous Media by Using Percolation Concepts

, Article Transport in Porous Media ; Volume 114, Issue 1 , 2016 , Pages 169-199 ; 01693913 (ISSN) Masihi, M ; Gago, P. A ; King, P. R ; Sharif University of Technology

Springer Netherlands 2016

Abstract

In this paper we present new methods to estimate the effective permeability (keff) of heterogeneous porous media with a wide distribution of permeabilities and various underlying structures, using percolation concepts. We first set a threshold permeability (kth) on the permeability density function and use standard algorithms from percolation theory to check whether the high permeable grid blocks (i.e., those with permeability higher than kth) with occupied fraction of “p” first forms a cluster connecting two opposite sides of the system in the direction of the flow (high permeability flow pathway). Then we estimate the effective permeability of the heterogeneous porous media in different...

Percolation-based effective permeability estimation in real heterogeneous porous media

, Article 15th European Conference on the Mathematics of Oil Recovery, 29 August 2016 through 1 September 2016 ; 2016 ; 9462821933 (ISBN); 9789462821934 (ISBN) Masihi, M ; Gago, P ; King, P ; DCSE; Schlumberger; Shell ; Sharif University of Technology

European Association of Geoscientists and Engineers 2016

Abstract

It has long been understood that flow behavior in heterogeneous porous media is largely controlled by the continuity of permeability contrasts. With this in mind, we are looking in new methods for a fast estimation of the effective permeability which concentrates on the properties of the percolating cluster. From percolation concepts we use a threshold permeability value (Kth) by which the gridblocks with the highest permeability values connect two opposite side of the system in the direction of the flow. Those methods can be applied to heterogeneous media of a range of permeabilities distribution and various underlying structures. We use power law relations and weighted power averages that...

Optimization of sputtering parameters for the deposition of low resistivity indium tin oxide thin films

, Article Acta Metallurgica Sinica (English Letters) ; Vol. 27, issue. 2 , Apr , 2014 , p. 324-330 Yasrebi, N ; Bagheri, B ; Yazdanfar, P ; Rashidian, B ; Sasanpour, P ; Sharif University of Technology

2014

Abstract

Indium tin oxide (ITO) thin films have been deposited using RF sputtering technique at different pressures, RF powers, and substrate temperatures. Variations in surface morphology, optical properties, and film resistances were measured and analyzed. It is shown that a very low value of sheet resistance (1.96 ω/sq.) can be achieved with suitable arrangement of the deposition experiments. First, at constant RF power, deposition at different pressure values is done, and the condition for achieving minimum sheet resistance (26.43 ω/sq.) is found. In the next step, different values of RF powers are tried, while keeping the pressure fixed on the previously found minimum point (1-2 Pa). Finally,...

Comparative assessment of gasification based coal power plants with various CO2 capture technologies producing electricity and hydrogen

, Article Energy and Fuels ; Volume 28, Issue 2 , 20 February , 2014 , Pages 1028-1040 ; ISSN: 08870624 Mukherjee, S ; Kumar, P ; Hosseini, A ; Yang, A ; Fennell, P ; Sharif University of Technology

2014

Abstract

Seven different types of gasification-based coal conversion processes for producing mainly electricity and in some cases hydrogen (H2), with and without carbon dioxide (CO2) capture, were compared on a consistent basis through simulation studies. The flowsheet for each process was developed in a chemical process simulation tool "Aspen Plus". The pressure swing adsorption (PSA), physical absorption (Selexol), and chemical looping combustion (CLC) technologies were separately analyzed for processes with CO2 capture. The performances of the above three capture technologies were compared with respect to energetic and exergetic efficiencies, and the level of CO2 emission. The effect of air...