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A signature-based approach of correctness assurance in data outsourcing scenarios
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) ; Volume 7093 LNCS , 2011 , Pages 374-378 ; 03029743 (ISSN) ; 9783642255595 (ISBN) ; Hadavi, M. A ; Jalili, R ; Sharif University of Technology
2011
Abstract
Correctness assurance of query results in data outsourcing scenarios includes authenticity, completeness, and freshness of the results. Utilizing signature chaining and aggregation, this paper proposes a method to verify the correctness of results returned from an untrusted server. An MHT constructed over attribute values of a tuple is used to provide the authenticity, and timestamp is used to provide the freshness verifiability of results. While our approach supports a wide range of queries, simulation results indicate its efficiency in comparison with some existing methods in terms of communication and computation overhead imposed to execute a query
Gas barrier properties of PP/EPDM blend nanocomposites
, Article Journal of Membrane Science ; Volume 282, Issue 1-2 , 2006 , Pages 142-148 ; 03767388 (ISSN) ; Dadbin, S ; Salehpour, Z ; Noferesti, M ; Sharif University of Technology
2006
Abstract
Nanocomposites of polypropylene (PP)/ethylene-propylene-diene rubber (EPDM) blend with montmorillonite-based organoclay were prepared in a solvent blending method. Solvent blending of PP and EPDM in a composition of 50:50 formed a two phase morphology in which EPDM appeared as dispersed phase with irregular shape. The size of dispersed phase reduced significantly to almost spherical domains by addition of the nanoclay. For better dispersion of nanoclay in the PP/EPDM blend, an antioxidant was used as compatibilizer. State of nanoclay dispersion was evaluated by X-ray diffraction (XRD), and also, by a novel method using permeability measurements data in a permeability model. The measured...
Query Correctness Assurance for Outsourced Databases
, M.Sc. Thesis Sharif University of Technology ; Jalili, Rasoul (Supervisor)
Abstract
In the secure data outsourcing scenario, verification of the reply of an unreliable server includes assessing the authenticity, completeness and it’s integrity. In this thesis, an efficient method, with emphasis on freshness, has been introduced to evaluate the correctness of the replies from a server. It takes in hand different application needs, inherent differences in the data, and different update mechanisms. This method evaluates freshness by using timestamps alongside the data being out sourced. Due to the requirement of verifying not only the freshness of the response, but the correctness of the timestamps as well, two general methods for evaluating and verifying the responses were...
HB2DS: a behavior-driven high-bandwidth network mining system
, Article Journal of Systems and Software ; Volume 127 , 2017 , Pages 266-277 ; 01641212 (ISSN) ; Jalili, R ; Sharif University of Technology
Elsevier Inc
2017
Abstract
This paper proposes a behavior detection system, HB2DS, to address the behavior-detection challenges in high-bandwidth networks. In HB2DS, a summarization of network traffic is represented through some meta-events. The relationships amongst meta-events are used to mine end-user behaviors. HB2DS satisfies the main constraints exist in analyzing of high-bandwidth networks, namely online learning and outlier handling, as well as one-pass processing, delay, and memory limitations. Our evaluation indicates significant improvement in big data stream analyzing in terms of accuracy and efficiency. © 2016 Elsevier Inc
Behavior-Driven Security Policy Enforcement on High Bandwidth Networks
, Ph.D. Dissertation Sharif University of Technology ; Jalili, Rasool (Supervisor)
Abstract
High-bandwidth network analysis is challenging, resource consuming, and inaccurate due to the high volume, velocity, and variety characteristics of the network traffic. Today's high-bandwidth networks require adaptive analyzing approaches to recognize the network variable behaviors. The analyzing approaches should be robust against the lack of prior knowledge and provide data to impose more complex policies.This thesis introduces complex policy relation and proposes a two-layer framework to enforce complex policies, named HB2DS. The proposed framework is equipped with the mechanism and policy layers. The mechanism layer processes network packets header and payload to generate a flow stream....
Inline high-bandwidth network analysis using a robust stream clustering algorithm
, Article IET Information Security ; Volume 13, Issue 5 , 2019 , Pages 486-497 ; 17518709 (ISSN) ; Jalili, R ; Sharif University of Technology
Institution of Engineering and Technology
2019
Abstract
High-bandwidth network analysis is challenging, resource consuming, and inaccurate due to the high volume, velocity, and variety characteristics of the network traffic. The infinite stream of incoming traffic forms a dynamic environment with unexpected changes, which requires analysing approaches to satisfy the high-bandwidth network processing challenges such as incremental learning, inline processing, and outlier handling. This study proposes an inline high-bandwidth network stream clustering algorithm designed to incrementally mine large amounts of continuously transmitting network traffic when some outliers can be dropped before determining the network traffic behaviour. Maintaining...
ACoPE: An adaptive semi-supervised learning approach for complex-policy enforcement in high-bandwidth networks
, Article Computer Networks ; Volume 166 , 2020 ; Jalili, R ; Sharif University of Technology
Elsevier B.V
2020
Abstract
Today's high-bandwidth networks require adaptive analyzing approaches to recognize the network variable behaviors. The analyzing approaches should be robust against the lack of prior knowledge and provide data to impose more complex policies. In this paper, ACoPE is proposed as an adaptive semi-supervised learning approach for complex-policy enforcement in high-bandwidth networks. ACoPE detects and maintains inter-flows relationships to impose complex-policies. It employs a statistical process control technique to monitor accuracy. Whenever the accuracy decreased, ACoPE considers it as a changed behavior and uses data from a deep packet inspection module to adapt itself with the change. The...
Distinguishing attack on bivium
, Article Proceedings - 10th IEEE International Conference on Computer and Information Technology, CIT-2010, 7th IEEE International Conference on Embedded Software and Systems, ICESS-2010, ScalCom-2010, 29 June 2010 through 1 July 2010, Bradford ; 2010 , Pages 1075-1078 ; 9780769541082 (ISBN) ; Rohani, N ; Mohajeri, J ; Aref, M. R ; Sharif University of Technology
2010
Abstract
Bivium is a simplified version of Trivium, a hardware profile finalist of eSTREAM project. Bivium has an internal state of size 177 bits and a key length of 80 bits. In this paper we introduce a distinguishing attack on this cipher. In this method we first find the best linear approximation for the updating function. Then by using this approximation, and optimizing the time delay, we find the distinguisher. The complexity of the attack is O(230.79), which is an improvement to the previous distinguishing attack with a complexity of order O(232)
The Model for Industrialization Feasibility of Projects on the Basis of Sustainable Development
, M.Sc. Thesis Sharif University of Technology ; Mortaheb, Mohammad Mehdi (Supervisor)
Abstract
Pre-fabrication of building components, as a level of industrial building, is an innovative method of construction, which is widely used in developed countries nowadays. However, this method has accounted for a small percentage of the construction in developing countries like Iran. On the other hand, it is essential to consider sustainable development with the incidence of issues such as degradation of natural resources and ecosystems, pollution, over population, injustice procedure, and decrease in quality of human life. Industrial building systems have a significant impact on improvement and expansion of sustainable development laws due to their potential characteristics. Hence, the...
Distinguishing Attacks on Stream Ciphers
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Mohajeri, Javad (Supervisor)
Abstract
Stream ciphers are cryptographic schemes being widely used in communications as a means of providing security of data. Hence, scrutinizing their level of security against different cryptanalytic methods has obviously turned to be of great importance. Randomness of the keystream is an important requirement for stream ciphers. The cipher should be designed in such a way that the keystream is free of any statistical biases that would let attackers distinguish it from a random sequence. A distinguishing attack on a stream cipher is one that determines whether a given stream of symbols is a truly random sequence or generated by a specific cipher with an unknown key. In this thesis, we focus on...
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
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...