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TCP retransmission timer adjustment mechanism using system identification
, Article Proceedings of the 2004 American Control Conference (AAC), Boston, MA, 30 June 2004 through 2 July 2004 ; Volume 3 , 2004 , Pages 2328-2332 ; 07431619 (ISSN); 0780383354 (ISBN) ; Rad, A. H. M ; American Automatic Control Council; International Federation of Automation Control, IFAC ; Sharif University of Technology
2004
Abstract
In this paper, the TCP retransmission timer adjustment mechanism is approached from the system's theoretic point of view. TCP uses a simple recursive system identification algorithm to capture both time variant and time invariant Internet behavior and provides a dynamic Round-Trip Time (RTT) predictor. Based on real Internet data collection, it is observed that when the retransmission timer is adjusted by using the proposed predictor instead of the traditional RTT estimator, its performance increases significantly
Dynamic classifier selection using clustering for spam detection
, Article 2009 IEEE Symposium on Computational Intelligence and Data Mining, CIDM 2009, Nashville, TN, 30 March 2009 through 2 April 2009 ; 2009 , Pages 84-88 ; 9781424427659 (ISBN) ; Beigy, H ; Sharif University of Technology
2009
Abstract
Most email users have encountered with spam problems, which have been addressed as a text classification or categorization problem. In this paper, we propose a novel spam detection method that uses ensemble of classifiers based on clustering and selection techniques. There is diversity in genre of e-mail's content and this method can find different topics in emails by clustering. It first computes disjoint clusters of emails, and then a classifier is trained on each cluster. When new email arrives, its cluster is identified. The classifier of the identified cluster is selected to classify the new email. Our method can extract many kinds of topics in emails. The evaluation shows that the...
An Efficient Approach for Spam Mail Detection in the Sender Side
, M.Sc. Thesis Sharif University of Technology ; Nemaney Pour, Alireza (Supervisor)
Abstract
Spam mails are unwanted mails sent to large numbers of users. Such emails not only consume the network resources but also cause lots of security uncertainties. Based on our observation, the location where the spam filters operate in is an important parameter to save network resources. In this thesis, we introduce a new and effective approach to avoid spam emails from being transferred by relocating the filtering system in the sender mail server. Compared with previous methods in our method, the spam email is detected after spammer clicks on the send button. Here the sender mail server decides based on some pre-defined criteria. If the sender mail server determines that the email is not spam,...
Power quality improvement in three-phase four-wire systems using shunt active filters
, Article 9th IEEE International Power Electronics Congress, CIEP 2004, Celaya, Gto, 17 October 2004 through 22 October 2004 ; 2004 , Pages 193-197 ; Parniani, M ; Mokhtari, H ; Sharif University of Technology
2004
Abstract
This paper presents a shunt active filter control using the instantaneous power theory on a rotating reference frame for power quality improvement in 3-phase 4-wire system. By current space vector mapping on rotating reference frame, three linearly independent components are derived. The defined powers can be controlled by current vector components. The in-phase current vector component to voltage vector is used for compensating oscillatory load active power and controlling dc voltage. Two other components are used to compensate for reactive power and to eliminate neutral current. Advantage of this control strategy is that synchronizing circuit is not required. Simulation results verify...
DWM-CDD: Dynamic weighted majority concept drift detection for spam mail filtering
, Article World Academy of Science, Engineering and Technology ; Volume 80 , 2011 , Pages 291-294 ; 2010376X (ISSN) ; Pour, A. N ; Sharif University of Technology
Abstract
Although e-mail is the most efficient and popular communication method, unwanted and mass unsolicited e-mails, also called spam mail, endanger the existence of the mail system. This paper proposes a new algorithm called Dynamic Weighted Majority Concept Drift Detection (DWM-CDD) for content-based filtering. The design purposes of DWM-CDD are first to accurate the performance of the previously proposed algorithms, and second to speed up the time to construct the model. The results show that DWM-CDD can detect both sudden and gradual changes quickly and accurately. Moreover, the time needed for model construction is less than previously proposed algorithms
Cloud assisted IOT based social door to boost student-professor interaction
, Article 18th International Conference on Posters’ Extended Abstracts, HCI International 2016, 17 July 2016 through 22 July 2016 ; Volume 618 , 2016 , Pages 426-432 ; 18650929 (ISSN); 9783319405414 (ISBN) ; Yassine, A ; Shirmohammadi, S ; Rasooli, R ; Arbabi, M. S ; Stephanidis C ; Sharif University of Technology
Springer Verlag
2016
Abstract
Face to face meetings and physical presence are important concepts in student-professor relations. Many students require flexibility in arranging meetings or the possibility of ad-hoc meeting with their professors. However, adhoc meetings could be difficult to arrange due to busy schedule of professors. It is not unusual for students to attempt several times in a day to catch a professor, or wait an hour behind his door. To overcome this challenge, some professors have teaching assistants (TAs) or office assistant who manage their schedule or provide students with helpful information on how to reach them or handover their documents, projects, etc. Many other professors do not have any...
On the evaluation of marton’s inner bound for two-receiver broadcast channels
, Article IEEE Transactions on Information Theory ; 2018 ; 00189448 (ISSN) ; Gohari, A ; Nair, C ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Marton’s inner bound is the best known achievable rate region for a general two-receiver discrete memoryless broadcast channel. In this paper, we establish improved bounds on the cardinalities of the auxiliary random variables appearing in this inner bound to the true rate region. We combine a perturbation technique, along with a representation using concave envelopes of information-theoretic functions that involve the use of auxiliary random variables, to achieve this improvement. The new cardinality bounds lead to a proof that a randomized time-division strategy achieves every rate triple in Marton’s region for binary input broadcast channels. This extends the result by Hajek and Pursley...
A fundamental tradeoff between computation and communication in distributed computing
, Article IEEE Transactions on Information Theory ; 2017 ; 00189448 (ISSN) ; Maddah Ali, M. A ; Yu, Q ; Avestimehr, A. S ; Sharif University of Technology
Abstract
How can we optimally trade extra computing power to reduce the communication load in distributed computing? We answer this question by characterizing a fundamental tradeoff between computation and communication in distributed computing, i.e., the two are inversely proportional to each other. More specifically, a general distributed computing framework, motivated by commonly used structures like MapReduce, is considered, where the overall computation is decomposed into computing a set of “Map” and “Reduce” functions distributedly across multiple computing nodes. A coded scheme, named “Coded Distributed Computing” (CDC), is proposed to demonstrate that increasing the computation load of the...
A fundamental tradeoff between computation and communication in distributed computing
, Article IEEE Transactions on Information Theory ; Volume 64, Issue 1 , 2018 , Pages 109-128 ; 00189448 (ISSN) ; Maddah Ali, M. A ; Yu, Q ; Salman Avestimehr, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
How can we optimally trade extra computing power to reduce the communication load in distributed computing? We answer this question by characterizing a fundamental tradeoff between computation and communication in distributed computing, i.e., the two are inversely proportional to each other. More specifically, a general distributed computing framework, motivated by commonly used structures like MapReduce, is considered, where the overall computation is decomposed into computing a set of “Map” and “Reduce” functions distributedly across multiple computing nodes. A coded scheme, named “coded distributed computing” (CDC), is proposed to demonstrate that increasing the computation load of the...
VSPACE: VNF simultaneous placement, admission control and embedding
, Article IEEE Journal on Selected Areas in Communications ; Volume 36, Issue 3 , 2018 , Pages 542-557 ; 07338716 (ISSN) ; Parsaeefard, S ; Maddah Ali, M. A ; Mahmoodi, T ; Khalaj, B. H ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
In future wireless networks, network functions virtualization lays the foundations for establishing a new dynamic resource management framework to efficiently utilize network resources. In this paper, a network service can be viewed as a chain of virtual network functions (VNFs), called a service function chain (SFC), served via placement, admission control (AC), and embedding into network infrastructure, based on the resource management objectives and the state of network. To fully exploit such a potential and reach higher network performance, resource management stages should be jointly performed. To this end, two main challenges are: how to present a system model that formulates the...
On the evaluation of marton's inner bound for two-receiver broadcast channels
, Article IEEE Transactions on Information Theory ; Volume 65, Issue 3 , 2019 , Pages 1361-1371 ; 00189448 (ISSN) ; Gohari, A ; Nair, C ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Marton's inner bound is the best known achievable rate region for a general two-receiver discrete memoryless broadcast channel. In this paper, we establish improved bounds on the cardinalities of the auxiliary random variables appearing in this inner bound to the true rate region. We combine a perturbation technique, along with a representation using concave envelopes of information-theoretic functions that involve the use of auxiliary random variables, to achieve this improvement. The new cardinality bounds lead to a proof that a randomized-time-division strategy achieves every rate triple in Marton's region for binary input broadcast channels. This extends the result by Hajek and Pursley...