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Gapprox: using gallup approach for approximation in big data processing
, Article Journal of Big Data ; Volume 6, Issue 1 , 2019 ; 21961115 (ISSN) ; Goudarzi, M ; Foroutan, F ; Sharif University of Technology
SpringerOpen
2019
Abstract
As Big Data processing often takes a long time and needs a lot of resources, sampling and approximate computing techniques may be used to generate a desired Quality of Result. On the other hand, due to not considering data variety, available sample-based approximation approaches suffer from poor accuracy. Data variety is one of the key features of Big Data which causes various parts of data to have different impact on the final result. To address this problem, we develop a data variety aware approximation approach called Gapprox. Our idea is to use a kind of cluster sampling to improve the accuracy of estimation. Our approach can decrease the amount of data to be processed to achieve the...
A multi-dimensional packet classifier for NP-based firewalls
, Article Proceedings - 2004 International Symposium on Applications and the Internet (Saint 2004), Tokyo, 26 January 2004 through 30 January 2004 ; 2004 , Pages 250-254 ; 0769520685 (ISBN); 9780769520681 (ISBN) ; Rabiee, H. R ; Foroutan, A ; Lavasani, M ; Sharif University of Technology
2004
Abstract
In this paper we present design and implementation of a new multi dimensional packet classifier engine using network processor technology. Our classification algorithm is fast and is based on hierarchical trie search for multi-dimensional rules. Moreover, we propose a technique to optimize the memory usage of our classifier. We have used the Intel® IXP1200 network processor pipeline architecture for implementation of the classifier. The final system is targeted to be a fast firewall packet filtering engine that uses the filtering policies as its classification rules. Our experimental result shows that the packet classification throughput results for various distribution of packet sizes, is...
The shape of two-dimensional and three-dimensional drops on flat and curved hydrophilic substrates: variational, numerical and molecular dynamics simulation investigations
, Article Journal of the Iranian Chemical Society ; 2021 ; 1735207X (ISSN) ; Torabi Rad, M ; Boudaghi, A ; Ataeizadeh, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2021
Abstract
In this paper, we analyze the shape of two-dimensional and three-dimensional drops on flat and curved substrates by minimizing free energy with the variational approach. The process initiated from the flat substrate and has proved the drop shape equation. Then, the drop shape equation for these models has been determined by extending the method to curved substrates. The constraints in 2D and 3D models are constant surface area and volume, respectively. The Euler–Lagrange differential equation can be solved analytically in the two-dimensional case and the drop height as a function of x has been driven which is the equation of a circle. In the 3D model, a fundamental partial differential...
The shape of two-dimensional and three-dimensional drops on flat and curved hydrophilic substrates: variational, numerical and molecular dynamics simulation investigations
, Article Journal of the Iranian Chemical Society ; Volume 19, Issue 2 , 2022 , Pages 423-433 ; 1735207X (ISSN) ; Torabi Rad, M ; Boudaghi, A ; Ataeizadeh, H ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
In this paper, we analyze the shape of two-dimensional and three-dimensional drops on flat and curved substrates by minimizing free energy with the variational approach. The process initiated from the flat substrate and has proved the drop shape equation. Then, the drop shape equation for these models has been determined by extending the method to curved substrates. The constraints in 2D and 3D models are constant surface area and volume, respectively. The Euler–Lagrange differential equation can be solved analytically in the two-dimensional case and the drop height as a function of x has been driven which is the equation of a circle. In the 3D model, a fundamental partial differential...
Security Analysis of an Offline Mobile Micro-Payment System
, M.Sc. Thesis Sharif University of Technology ; Goudarzi, Maziar (Supervisor)
Abstract
Mobile payment has already become an integral part of modern life for daily banking needs. Many payment systems are now providing financial services to customers. Most of these systems need and rely on online network access to provide their services. On the other hand, there are many regions in the world that have no network access or the network quality is poor with intermittent failures. Customers in these areas are unable to transfer money or buy goods and pay for it using their mobile devices by such above systems. This motivated us to find a way for transferring money without need for network availability. As a result we devised an offline peer-to peer mobile payment system (MobiPOS)....
Planning the Standards and Instructions Required to Implement BIM Principal in Iran
, M.Sc. Thesis Sharif University of Technology ; Alvanchi, Amin (Supervisor)
Abstract
Preparation of a vision document, strategic plan and appropriate roadmap for the development of BIM in the country has a key role in the success of BIM implementation in the construction industry. Therefore, in this study, we tried to study the obstacles and challenges in Iran. In order to achieve the desired result, first the status of BIM use in 6 selected countries with different levels of development was examined. Then, by examining the international documents and standards of BIM in the leading countries of the world and the relationship between these documents and standards, they determined the success indicators, challenges and obstacles of BIM implementation and tried to explain the...
An improved scheme for pre-computed patterns in core-based SoC architecture
, Article Proceedings of 2016 IEEE East-West Design and Test Symposium, EWDTS 2016, 14 October 2016 through 17 October 2016 ; 2017 ; 9781509006939 (ISBN) ; Rahimi, R ; Foroutan, P ; Fathy, M ; Navabi, Z ; Sharif University of Technology
2017
Abstract
By advances in technology, integrated circuits have come to include more functionality and more complexity in a single chip. Although methods of testing have improved, but the increase in complexity of circuits, keeps testing a challenging problem. Two important challenges in testing of digital circuits are test time and accessing the circuit under test (CUT) for testing. These challenges become even more important in complex system on chip (SoC) zone. This paper presents an improved scheme for generating pre-computed test patterns in core-based systems on chip. This approach reduces the number of pre-computed test patterns and as the result, test application time (TAT) will be decreased....
Probability of missed detection as a criterion for receiver placement in MIMO PCL
, Article IEEE National Radar Conference - Proceedings, 7 May 2012 through 11 May 2012, Atlanta, GA ; 2012 , Pages 0924-0927 ; 10975659 (ISSN) ; 9781467306584 (ISBN) ; Chitgarha, M. M ; Radmard, M ; Nayebi, M. M ; Sharif University of Technology
IEEE
2012
Abstract
Using multiple antennas at the transmit and receive sides of a passive radar brings both the benefits of MIMO radar and passive radar. However one of the obstacles arisen in such configuration is the receive antennas placement in proper positions so that the radar performance is improved. Here we just consider the case of positioning one receiver among multiple illuminators of opportunity. Indeed it is a start for the solution of optimizing the geometry of the multiple receivers in a passive radar
An efficient method for the ring opening of epoxides with aromatic amines by Sb(III) chloride under microwave irradiation
, Article Journal of Chemical Research ; Issue 4 , 2008 , Pages 220-221 ; 03082342 (ISSN) ; Hashemi, M. M ; Mottaghi, M. M ; Foroughi, M. M ; Sharif University of Technology
2008
Abstract
SbCl3 supported on montmorillonite K-10 is an efficient catalyst for the ring opening of epoxides with aromatic amines under solvent-free conditions and microwave irradiation to give the corresponding b-amino alcohols in high yields with high regioselectivity
Resource allocation for uav-enabled integrated sensing and communication (isac) via multi-objective optimization
, Article ICASSP, IEEE International Conference on Acoustics, Speech and Signal Processing - Proceedings ; Volume 2023-June , 2023 ; 15206149 (ISSN); 978-172816327-7 (ISBN) ; Naghsh, M. M ; Karbasi, M ; Nayebi, M. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2023
Abstract
In this paper, we consider an integrated sensing and communication (ISAC) system with wireless power transfer (WPT) where an unmanned aerial vehicle (UAV)-based radar serves a group of energy-limited communication users in addition to its sensing functionality. In this architecture, the radar senses the environment in phase 1 (namely sensing phase) and mean-while, the communications users (nodes) harvest and store the energy from the radar transmit signal. The stored energy is then used for information transmission from the nodes to UAV in phase 2, i.e., uplink phase. Performance of the radar system depends on the transmit signal as well as the receive filter; the energy of the transmit...
MIMO radar signal design to improve the MIMO ambiguity function via maximizing its peak
, Article Signal Processing ; Volume 118 , 2016 , Pages 139-152 ; 01651684 (ISSN) ; Radmard, M ; Nazari Majd, M ; Karbasi, S. M ; Nayebi, M. M ; Sharif University of Technology
Elsevier
2016
Abstract
One of the important obstacles in MIMO (Multiple Input Multiple Output) radars is the issue of designing proper transmit signals. Indeed, the capability of signal design is a significant advantage in MIMO radars, through which, the system can achieve much better performance. Many different aspects of this performance improvement have been considered yet, and the transmit signals have been designed to attain such goal, e.g., getting higher SNR or better detector's performance at the receiver. However, an important tool for evaluating the radar's performance is its ambiguity function. In this paper, we consider the problem of transmit signal design, in order to optimize the ambiguity function...
Detection-localization tradeoff in MIMO radars
, Article Radioengineering ; Volume 26, Issue 2 , 2017 , Pages 581-587 ; 12102512 (ISSN) ; Radmard, M ; Chitgarha, M. M ; Bastani, M. H ; Nayebi, M. M ; Sharif University of Technology
2017
Abstract
Two gains play key roles in recently developed MIMO wireless communication systems: "spatial diversity" gain and "spatial multiplexing" gain. The diversity gain refers to the capability to decrease the error rate of the MIMO channel, while the multiplexing gain implicitly refers to the amount of increase in the capacity of the MIMO channel. It has been shown that there is a fundamental tradeoff between these two types of gains, meaning interplay between increasing reliability (via an increase in the diversity gain) and increasing data rate (via an increase in the multiplexing gain). On the other hand, recently, MIMO radars have attracted much attention for their superior ability to enhance...
Antenna placement and power allocation optimization in MIMO detection
, Article IEEE Transactions on Aerospace and Electronic Systems ; Vol. 50, Issue 2 , April , 2014 , pp. 1468-1478 ; Chitgarha, M. M ; Majd, M. N ; Nayebi, M. M ; Sharif University of Technology
2014
Abstract
It is a well known fact that using multiple antennas at transmit and receive sides improves the detection performance. However, in such multiple-input multiple-output (MIMO) configuration, proper positioning of transmitters and receivers is a big challenge that can have significant influence on the performance of the overall system. In addition, determining the power of each transmitter under a total power constraint is a problem that should be solved in order to enhance the performance and coverage of such a system. In this paper, we design the Neyman-Pearson detector under the Rayleigh scatter model and use it to introduce a criterion for the antenna placement at both transmit and receive...
Ambiguity function of MIMO radar with widely separated antennas
, Article Proceedings International Radar Symposium ; 16 -18 June , 2014 ; ISSN: 21555753 ; Chitgarha, M. M ; Nazari Majd, M ; Nayebi, M. M ; Sharif University of Technology
2014
Abstract
There has been much interest, recently, towards exploiting the Multiple-Input Multiple-Output (MIMO) technique in radar. It is shown that using multiple antennas at transmit and receive sides can improve the performance of the system. However, in order to analyze the system's performance, its ambiguity function, i.e. the ambiguity function of a MIMO radar, is needed to be defined. In this paper, beginning from the information theoretic definitions, we derive such function, specifically for a MIMO radar with widely separated antennas
Choosing the position of the receiver in a MISO passive radar system
, Article European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 9th European Radar Conference, EuRAD 2012 ; 2012 , Pages 318-321 ; 9782874870293 (ISBN) ; Majd, M. N ; Radmard, M ; Nayebi, M. M ; Sharif University of Technology
2012
Abstract
By combining the two ideas of MIMO (Multiple Input Multiple Output) and PCL (Passive Coherent Location) in radar, one can achieve the advantages of both recently developed techniques simultaneously. While using multiple antennas at the receive side provides a spatial diversity of the object to be detected, using multiple illuminators of opportunity, most importantly, makes the radar covert to the interceptors. One obstacle in such MIMO configuration is choosing the positions of the receive antennas. In this paper, after analyzing the Neyman-Pearson detector for the DVB-T based PCL, we introduce the probability of missed detection as a criterion to place the receive antenna. Here, we only...
Adaptive filtering techniques in passive radar
, Article Proceedings International Radar Symposium, Dresden ; Volume 2 , June , 2013 , Pages 1067-1078 ; 21555753 (ISSN) ; 9783954042234 (ISBN) ; Radmard, M ; Majd, M. N ; Nayebi, M. M ; Sharif University of Technology
2013
Abstract
One of the most important obstacles in passive radar applications is removing the direct signal from the target channel. Otherwise, week echoes from the targets in the target channel would be ignored due to the limited dynamic range of the system. One of the most effective techniques in this field is using adaptive filters. In this paper various adaptive filters are introduced and their performances are shown and compared
Ambiguity function based receiver placement in multi-site radar
, Article 2016 CIE International Conference on Radar, RADAR 2016, 10 October 2016 through 13 October 2016 ; 2017 ; 9781509048281 (ISBN) ; Chitgarha, M. M ; Nazari Majd, M ; Nayebi, M. M ; Sharif University of Technology
2017
Abstract
It has been shown that using multiple antennas in a radar system improves the performance considerably, since multiple target echoes are received from different aspect angles of the target. In this way, the target detection is improved. However, when using multiple antennas, some problems, such as designing the transmit signals, synchronization, etc. emerge that should be solved. One of such problems is the receiver placement. Receiver placement deals with choosing a proper position for the receive antenna in order to optimize the whole system's performance. In this paper, a receiver placement procedure based on improving the radar ambiguity function is proposed for the case of a multisite...
Improving MIMO radar's performance through receivers' positioning
, Article IET Signal Processing ; Volume 11, Issue 5 , 2017 , Pages 622-630 ; 17519675 (ISSN) ; Radmard, M ; Nazari Majd, M ; Nayebi, M. M ; Sharif University of Technology
Institution of Engineering and Technology
2017
Abstract
By employing the MIMO (multiple-input-multiple-output) technology in radar, some new problems emerged, that, in order to benefit the MIMO gains in radar, it was necessary to solve them suitably. One of such obstacles is determining the positions of receive antennas in a MIMO radar system with widely separated antennas (WS MIMO radar), since it is shown that the antennas' positions affect the whole system's performance considerably. In this study, a proper receivers' positioning procedure is proposed. To do this end, four criteria are developed based on the proposed MIMO detector and the MIMO ambiguity function. The simulations verify that the proposed positioning procedure improves the...
Silylation of hydroxy groups with HMDS under microwave irradiation and solvent-free conditions
, Article Phosphorus, Sulfur and Silicon and Related Elements ; Volume 177, Issue 2 , 2002 , Pages 289-292 ; 10426507 (ISSN) ; Saidi, M. R ; Bolourtchian, M ; Heravi, M. M ; Sharif University of Technology
2002
Abstract
Phenols and alcohols are silylated with hexamethyldisilazane (HMDS) under microwave irradiation in solvent-free condition in good to excellent yields
Dynamic analysis of carbon nanotubes under electrostatic actuation using modified couple stress theory
, Article Acta Mechanica ; Vol. 225, Issue 6 , June , 2014 , pp. 1523-1535 ; Online ISSN: 1619-6937 ; Rastgoo, A ; Ahmadian, M. T ; Mashhadi, M. M ; Sharif University of Technology
2014
Abstract
Modified couple stress theory is a size-dependent theorem capturing the micro/nanoscale effects influencing the mechanical behaviors of the micro- and nanostructures. In this paper, it is applied to investigate the nonlinear vibration of carbon nanotubes under step DC voltage. The vibration, natural frequencies and dynamic pull-in characteristics of the carbon nanotubes are studied in detail. Moreover, the effects of various boundary conditions and geometries are scrutinized on the dynamic characteristics. The results reveal that application of this theory leads to the higher values of the natural frequencies and dynamic pull-in voltages