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Distributed Optimal Control Based on an Efficient Method for Communication
, M.Sc. Thesis Sharif University of Technology ; Farhadi, Alireza (Supervisor)
Abstract
This thesis is concerned with an optimal trade-off between communication overhead and the number and size of neighborhoods in a distributed optimal control technique for large-scale systems that is based on the Jacobi iteration and two-layer architecture for communication. Although this method efficiently reduces computational overhead, continuous and proper data transfer between subsystems that are very often far from each other, is required to achieve an acceptable performance. However, limited transmission bandwidth and short communication range result in significant communication overhead. This causes significant time latency between measurement and applied calculated control actions,...
Computation time analysis of centralized and distributed optimization algorithms applied to automated irrigation networks
, Article 2013 3rd Australian Control Conference, AUCC 2013, Fremantle, WA ; Nov , 2013 , Pages 263-269 ; 9781479924981 (ISBN) ; Dower, P. M ; Cantoni, M ; Sharif University of Technology
2013
Abstract
This paper compares the computation time of two algorithms for solving a structured constrained linear optimal control problem with finite horizon quadratic cost within the context of automated irrigation networks. The first is a standard centralized algorithm based on the active set method that does not exploit problem structure. The second is distributed and is based on a consensus algorithm, not specifically tailored to account for system structure. It is shown that there is a significant advantage in terms of computation overhead (the time spent computing the optimal solution) in using the second algorithm in large-scale networks. Specifically, for a fixed horizon length the computation...
Modeling of CO2 solubility in brine by using neural networks
, Article Saint Petersburg 2012 - Geosciences: Making the Most of the Earth's Resources, 2 April 2012 through 5 April 2012 ; April , 2012 ; Salami, H ; Taghikhani, V ; Sharif University of Technology
European Association of Geoscientists and Engineers, EAGE
2012
Abstract
CO2 sequestration in geological formations, such as aquifers, is known to be the best short-term solution to CO2 mitigation. Accurate description of CO2 solubility in brine is important for evaluating the capacity of aquifers to sequester CO2. Currently, EOS-based models are widely used in reservoir compositional simulators for this purpose. However, most of these models involve complex and iterative calculations which take too much time in case of large-scale flow simulation of geological CO2 storage. In this study, a neural network model is presented for prediction of CO2 solubility in brine which is highly accurate with less computational overhead
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
A verifiable delegated set intersection without pairing
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 2047-2051 ; 9781509059638 (ISBN) ; Ameri, M. H ; Mohajeri, J ; Aref, M. R ; Sharif University of Technology
Abstract
Recently, there has been shown a great interest in the private set intersection (PSI) protocols which are widely used in social networks applications. In a PSI protocol two entities are able to find the intersection of their document set without inferring more information than the common data. In some PSI protocols the process of finding the intersections of the documents are delegated to a third entity like cloud which has high computational and storage resources and the clients can verify the accuracy of the received results. These protocols are known as the Verifiable Delegated Set Intersection (VDSI). In this paper, we proposed an efficient VDSI protocol by employing the El-Gamal...
An efficient secure scheme for lossy and lossless data aggregation in smart grid
, Article 9th International Symposium on Telecommunication, IST 2018, 17 December 2018 through 19 December 2018 ; 2019 , Pages 528-534 ; 9781538682746 (ISBN) ; Forghani, P ; Ameri, M. H ; Aref, M. R ; Salmasizadeh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we propose an efficient secure data aggregation scheme for the smart grid, which supports both lossy and lossless data aggregation. In order to reduce the computational overhead of the control center, our proposed model includes a number of entities, called gateways, which act as intermediaries between the users and the control center. At the end of each measurement interval, each user generates a report which is encrypted using the Paillier cryptosystem and contains the user's consumption amount during the previous measurement interval as well as his or her prediction of consumption during another interval in the future. After receiving the user's reports, gateways perform...
Modification in Topology and Control Method for Improving Performance of Modular Multilevel Converter in 2N+1 and N+1 Modulation
, M.Sc. Thesis Sharif University of Technology ; Parniani, Mostafa (Supervisor)
Abstract
In Modular Multilevel converter, it is necessary to attain different objectives simultaneously. One of the most effective control methods which can cope with this kind of systems is the Model Predictive Control (MPC). This method predicts the values of control objectives based on different feasible states and determines the optimal one using cost functions. The number of feasible states can increase when the number of switches increases in the converter. This makes the MPC unable to be applied in the MMCs with hundereds of submodules (SMs) in each arm because of its heavy computational burden. In this thesis, a modified model predictive control is proposed to reduce the computational burden....
A new method of mining data streams using harmony search
, Article Journal of Intelligent Information Systems ; Volume 39, Issue 2 , 2012 , Pages 491-511 ; 09259902 (ISSN) ; Abolhassani, H ; Beigy, H ; Sharif University of Technology
Springer
2012
Abstract
Incremental learning has been used extensively for data stream classification. Most attention on the data stream classification paid on non-evolutionary methods. In this paper, we introduce new incremental learning algorithms based on harmony search. We first propose a new classification algorithm for the classification of batch data called harmony-based classifier and then give its incremental version for classification of data streams called incremental harmony-based classif ier. Finally, we improve it to reduce its computational overhead in absence of drifts and increase its robustness in presence of noise. This improved version is called improved incremental harmony-based classifier. The...
Fully distributed ECC-based key management for mobile ad hoc networks
, Article Computer Networks ; Volume 113 , 2017 , Pages 269-283 ; 13891286 (ISSN) ; Moradlou, Z ; Doostari, M. A ; Movaghar, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Dynamic nature of mobile ad hoc networks combined with their lack of centralized infrastructure make security problem the most challenging issue in such networks. The main contribution of this paper is to propose a secure and efficient key management algorithm, able to satisfying the requirement of such networks and facing their specific characteristics. The proposed algorithm is a fully distributed ID-based system which is built based on elliptic curve cryptography. The main advantage of the proposed algorithm, that gives it the superiority in its field of research, is the improvement of the performance and the security strength together. The proposed algorithm is implemented with much...
A secure key management framework for heterogeneous wireless sensor networks
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 19 October 2011 through 21 October 2011 ; Volume 7025 LNCS , October , 2011 , Pages 18-31 ; 03029743 (ISSN) ; 9783642247118 (ISBN) ; Aref, M. R ; Sharif University of Technology
2011
Abstract
A Wireless sensor network (WSN) is composed of numerous sensor nodes with both insecurely limited hardware and restricted communication capabilities. Thus WSNs suffer from some inherent weaknesses. Key management is an interesting subject in WSNs because it is the fundamental element for all security operations. A few key management models for heterogeneous sensor networks have been proposed in recent years. In this paper, we propose a new key management scheme based on elliptic curve cryptography and signcryption method for hierarchical heterogeneous WSNs. Our scheme as a secure infrastructure has superior sensor node mobility and network scalability. Furthermore, we propose both a periodic...
A secure and efficient authentication technique for vehicular Ad-Hoc networks
, Article IEEE Transactions on Vehicular Technology ; Volume 67, Issue 6 , 2018 , Pages 5409-5423 ; 00189545 (ISSN) ; Salmasizadeh, M ; Susilo, W ; Majidi, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
Vehicular ad-hoc networks (VANETs) are under active development, thanks in part to recent advances in wireless communication and networking technologies. The most fundamental part in VANETs is to enable message authentications between vehicles and roadside units. Message authentication using proxy vehicles has been proposed to reduce the computational overhead of roadside units significantly. In this message authentication scheme, proxy vehicles that verify multiple messages at the same time improve roadside units' efficiency. In this paper, first we show that the only proxy-based authentication scheme (PBAS) presented for this goal by Liu et al. cannot guarantee message authenticity, and...
GSL-AKA: group-based secure lightweight authentication and key agreement protocol for M2M communication
, Article 9th International Symposium on Telecommunication, IST 2018, 17 December 2018 through 19 December 2018 ; 2019 , Pages 275-280 ; 9781538682746 (ISBN) ; Mohajeri, J ; Salmasizadeh, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Nowadays, one of the most important criterions in designing of different generations of mobile cellular technology is to handle a large number of heterogeneous devices with high security guarantees. The first significant security issue considered in this field is mutual authentication of the devices and the network and key agreement between them. Hence, various authentication and key agreement (AKA) protocols were proposed for Long Term Evolution (LTE) and future 5G networks. However, each of the protocols suffers from security and non-security problems. This paper proposed a group-based secure lightweight authentication and key agreement (GSL- AKA) protocol for machine-to-machine (M2M)...
A cyber-physical system for building automation and control based on a distributed MPC with an efficient method for communication
, Article European Journal of Control ; Volume 61 , 2021 , Pages 151-170 ; 09473580 (ISSN) ; Farhadi, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
This paper introduces a cyber-physical system for building automation and control that is developed based on a distributed model predictive control. The implemented distributed method significantly reduces computation overhead with respect to the centralized methods. However, continuous data transfer between subsystems, which are often far from each other, is required when using this method. Information transmission between subsystems is very often subject to the limitations of transmission bandwidth and/or short communication range resulting in significant communication overhead. This causes significant time latency between making measurements and applying control commands, which adversely...