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Generalised secure distributed source coding with side information
, Article IET Communications ; Volume 4, Issue 18 , 2010 , Pages 2262-2272 ; 17518628 (ISSN) ; Salmasizadeh, M ; Aref, M. R ; Sharif University of Technology
2010
Abstract
New inner and outer bounds on the achievable compression-equivocation rate region for generalised secure data compression with side information are given that do not match in general. In this setup, two senders, Alice and Charlie intend to transmit information to Bob via channels with limited capacity so that he can reliably reconstruct their observations. The eavesdropper, Eve, has access to one of the channels at each instant and is interested in the source of the same channel at the time. Bob and Eve also have their own observations, which are correlated with Alice's and Charlie's observations. In this model, two equivocation and compression rates are defined with respect to the sources...
On the achievable rate region of a new Gaussian wiretap channel with side information
, Article 2012 IEEE Information Theory Workshop, ITW 2012, 3 September 2012 through 7 September 2012 ; September , 2012 , Pages 657-661 ; 9781467302234 (ISBN) ; Seyfe, B ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
2012
Abstract
This paper introduces a new applicable Gaussian wiretap channel with side information. In this channel, the state of the channel to the wiretapper is separated from the main channel's one. It means that the legitimate receiver and the wiretapper are listening to the transmitted signal through the different channels with different channel states which may have some correlation to each other. The state of the main channel, is assumed to be known at the transmitter, helps the sender to encrypt its messages. The achievable equivocation-rate region for this model is drived in the Gaussian case and the results are reduced to the previous works as special cases
Private Information Retrieval for a Multi-Message Scenario with Private Side Information
, Article IEEE Transactions on Communications ; Volume 69, Issue 5 , 2021 , Pages 3235-3244 ; 00906778 (ISSN) ; Shariatpanahi, S. P ; Maddah Ali, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
We consider the problem of private information retrieval (PIR), where a single user with private side information (PSI) aims to retrieve multiple files from a library stored at some servers. We assume that the side information (SI) at the user includes a subset of files stored privately. Moreover, the identity of requests and side information at the user are not revealed to any of the servers. The problem involves finding the minimum load transmitted from the servers to the user such that the requested files can be decoded with the help of received data and side information. By providing matching lower and upper bounds for certain regimes, we characterize the minimum load imposed on all the...
Clustering based on the Structure of the Data and Side Information
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
Clustering is one of the important problems in machine learning, data mining, and pattern recognition fields. When the considered feature space for data representation is not suitable for discrimination of data groups, the data clustering problem may be a difficult problem that cannot be solved properly. In the other words, when the Euclidean distance cannot describe the dissimilarity of data pairs appropriately, the common clustering algorithms may not be helpful and the clusters show arbitrary shapes and spread in such spaces. Although since the late 1990’s several algorithms have been proposed for finding clusters of arbitrary structures, these algorithms cannot yield desirable...
Active Constraint Clustering by Instance-level Constraint Ranking Using Estimated Cluster Boundaries
, M.Sc. Thesis Sharif University of Technology ; Beigy, Hamid (Supervisor)
Abstract
Taking into account the fast and ever-increasing pace of data growth, clustering algorithms emerge as the key tools for data analysis in new researches. Clustering remain as a method for decomposing data into clusters, in such a way that similar data coalesce in the same group. Different algorithms conduct clustering according to a series of initial hypotheses, without being informed about the clusters’ form and aims. Hence, in case with no conformity between initial hypothesis and the clustering aim, one cannot expect adequate response from the clustering algorithm. Exploitation of side information in clustering can play an impactful role in introduction of real models into clustering...
Analysis of Secret Key Agreement in The Channel Model with Side Information
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor)
Abstract
In this thesis, the problem of secret key agreement in the channel model with side information is studiedx. In order to investigate the problem, we consider three models according to the different ways of side information availability which are the state-dependent broadcast channel; the state-dependent broadcast channel in presence of public channel and the state-dependent wiretap channel with degraded versions of the channel state information.For the problem of secret key agreement in broadcast channels, two models, the state-dependent wiretap channel and state-dependent three receivers broadcast channel, are considered. We obtain inner and outer bounds of the secret key capacity region for...
Polar codes for a quadratic-Gaussian Wyner-Ziv problem
, Article Proceedings of the International Symposium on Wireless Communication Systems ; 2013 , Pages 718-722 ; 21540217 (ISSN) ; 9783800735297 (ISBN) ; Behroozi, H ; Sharif University of Technology
2013
Abstract
In this work, we study the performance of polar codes for lossy compression of a Gaussian source with a side information at decoder; known as the quadratic-Gaussian Wyner-Ziv problem. First we extend the binary polar codes to q-ary for the Wyner-Ziv problem. We show that the nested q- Ary polar codes are optimal for this case. Then we present two polar coding schemes for the Gaussian Wyner-Ziv problem. In the first scheme, we achieve a rate above the Wyner-Ziv rate-distortion function with a gap of 0.5 bits compared with the optimal rate. This scheme utilizes a successive cancellation decoder and is optimal in weak side-information cases when the decoder side-information noise variance is...
On the secrecy of the cognitive interference channel with partial channel states
, Article Transactions on Emerging Telecommunications Technologies ; Volume 27, Issue 11 , 2016 , Pages 1472-1485 ; 21615748 (ISSN) ; Seyfe, B ; Mirmohseni, M ; Aref, M. R ; Sharif University of Technology
Wiley Blackwell
2016
Abstract
The secrecy problem in the state-dependent cognitive interference channel is considered in this paper. In our model, there are a primary and a secondary (cognitive) transmitter–receiver pairs, in which the cognitive transmitter has the message of the primary one as side information. In addition, the channel is affected by two channel state sequences, which are known at the cognitive transmitter and the corresponding receiver, separately. The cognitive transmitter should cooperate with the primary one, and it wishes to keep its message secure at the primary receiver. The achievable equivocation-rate regions for this channel are derived using two approaches: the binning scheme coding and...
An attribute learning method for zero-shot recognition
, Article 2017 25th Iranian Conference on Electrical Engineering, ICEE 2017, 2 May 2017 through 4 May 2017 ; 2017 , Pages 2235-2240 ; 9781509059638 (ISBN) ; Shojaee, S. M ; Soleymani Baghshah, M ; Sharif University of Technology
Abstract
Recently, the problem of integrating side information about classes has emerged in the learning settings like zero-shot learning. Although using multiple sources of information about the input space has been investigated in the last decade and many multi-view and multi-modal learning methods have already been introduced, the attribute learning for classes (output space) is a new problem that has been attended in the last few years. In this paper, we propose an attribute learning method that can use different sources of descriptions for classes to find new attributes that are more proper to be used as class signatures. Experimental results show that the learned attributes by the proposed...
Time-Sharing improves dynamic index coding delay
, Article 2019 Iran Workshop on Communication and Information Theory, IWCIT 2019, 24 April 2019 through 25 April 2019 ; 2019 ; 9781728105840 (ISBN) ; Mojahedian, M. M ; Aref, M. R ; Pakravan, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this paper, we show how time-sharing method may reduce transmission delay in the dynamic index coding scenario. We propose a novel time-shared dynamic index coding transmission scheme that achieves the maximum index coding gain for a complete bi-directional side information graph and formulate a constrained optimization problem to tune the transmission scheme for the minimum transmission delay. A closed-form solution is presented for the special case of two-user. We also use analytical and simulation results to provide graphical intuition for the obtained results
Multi-message private information retrieval with private side information
, Article 2018 IEEE Information Theory Workshop, ITW 2018, 25 November 2018 through 29 November 2018 ; 2019 ; 9781538635995 (ISBN) ; Jafari Siavoshani, M ; Maddah Ali, M. A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
We consider the problem of private information retrieval (PIR) where a single user with private side information aims to retrieve multiple files from a library stored (uncoded) at a number of servers. We assume the side information at the user includes a subset of files stored privately (i.e., the server does not know the indices of these files). In addition, we require that the identity of requests and side information at the user are not revealed to any of the servers. The problem involves finding the minimum load to be transmitted from the servers to the user such that the requested files can be decoded with the help of received and side information. By providing matching lower and upper...
Analysis of Side Information in Series Relay Network
, M.Sc. Thesis Sharif University of Technology ; Aref, Mohammad Reza (Supervisor) ; Ashtiani, Farid (Supervisor)
Abstract
In this dissertation we discuss various results presented in the literature on single user channels with causal or noncausal side information and multiuser channels with side information such as multiple access channel and broadcast channel. The Series Relay Networks (SRN) with delays, with and without channel state information (CSI) are investigated from an information theoretic point of view. For SRN with unlimited look ahead where the relays can use the whole received block to encode, upper and lower bounds on the capacity are derived which are tight for the degraded case. For SRN without-delay where the relays have access to the present received symbols in addition to the past symbols,...
Distributed Learning in Wireless Sensor Networks
, Ph.D. Dissertation Sharif University of Technology ; Bagheri Shouraki, Saeed (Supervisor)
Abstract
Wireless Sensor Networks (WSNs) attracted lots of researchers in recent years, these sensors are small and have limited computational resources and are not expensive in comparision with conventional sensors. These sensors can sense, measure, gathering information from environment and send them to user, they are typically characterized by limited communication capabilities due to tight energy and bandwidth constraints. As a result, WSNs have inspired a resurgence in research on decentralized algorithms, structure of these networks are variable and dynamic, sensors may deleted from the network or added to the network, so using models which don’t require precies specifications of environment is...
On source transmission over some classes of relay channels
, Article IEEE International Symposium on Information Theory - Proceedings ; 2012 , Pages 1942-1946 ; 9781467325790 (ISBN) ; Aref, M. R ; Sharif University of Technology
IEEE
2012
Abstract
We study the reliable transmission of correlated sources over the relay channel. One of the sources is available at the sender while the other one is known to the relay. The receiver wishes to reconstruct both sources. We find necessary and sufficient conditions for optimal separation of source and channel codes. The coding scheme is based on the combination of the Slepian-Wolf source coding and Partial Decode-and-Forward (PDF) strategy. In this scheme, the relay partially decodes the message transmitted by the sender. We also consider the semi-deterministic relay channel where the output at the relay is a deterministic function of inputs from the sender and the relay. For the transmission...
Nonlinear blind source separation for sparse sources
, Article European Signal Processing Conference, 28 August 2016 through 2 September 2016 ; Volume 2016-November , 2016 , Pages 1583-1587 ; 22195491 (ISSN) ; 9780992862657 (ISBN) ; Rivet, B ; Jutten, C ; Babaie Zadeh, M ; Sharif University of Technology
European Signal Processing Conference, EUSIPCO
2016
Abstract
Blind Source Separation (BSS) is the problem of separating signals which are mixed through an unknown function from a number of observations, without any information about the mixing model. Although it has been mathematically proven that the separation can be done when the mixture is linear, there is not any proof for the separability of nonlinearly mixed signals. Our contribution in this paper is performing nonlinear BSS for sparse sources. It is shown in this case, sources are separable even if the problem is under-determined (the number of observations is less than the number of source signals). However in the most general case (when the nonlinear mixing model can be of any kind and there...
Dynamic index coding gain over a complete bi-directional side information graph
, Article IWCIT 2016 - Iran Workshop on Communication and Information Theory, 3 May 2016 through 4 May 2016 ; 2016 ; 9781509019229 (ISBN) ; Mojahedian, M. M ; Aref, M. R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
Dynamic Index coding as a generalization of the traditional index coding problem, deals with transmission of some dynamic data flows in the presence of side information. For a dynamic index coding system, the set of average flow rates for which the system can be stable is named Code-Constraint Capacity region. In this paper, we identify the code-constraint capacity region for a dynamic index coding problem with complete bi-directional side information graph. Furthermore, we introduce the concept of Dynamic Index Coding Gain to quantify the improvement resulted from the dynamic index coding with respect to uncoded transmissions. We also provide some corollaries about system performance...
Reliable source transmission over relay networks with side information
, Article 2009 IEEE International Symposium on Information Theory, ISIT 2009, Seoul, 28 June 2009 through 3 July 2009 ; 2009 , Pages 699-703 ; 21578102 (ISSN); 9781424443130 (ISBN) ; Akhbari, B ; Mohsenzadeh, V ; Aref, M. R ; Sharif University of Technology
2009
Abstract
In this paper, we consider reliable transmission of a discrete memoryless source over multi-relay networks with correlated Side Information (SI) available at the relay nodes and the final receiver. We obtain a necessary condition for reliable source transmission over a multi-terminal network with SI, which results in a necessary condition for a multi-relay network with SI, as a special case. We also propose a separate source-channel coding scheme, and based on it, a sufficient condition for a multi-relay network with SI is derived. Based on a partitioning method and the nature of a degraded relay network, we propose another coding scheme which results in a sufficient condition for a degraded...
On the devroye-mitran-tarokh rate region for the cognitive radio channel
, Article IEEE Transactions on Wireless Communications ; Volume 8, Issue 7 , 2009 , Pages 3458-3461 ; 15361276 (ISSN) ; Aref, M. R ; Sharif University of Technology
2009
Abstract
An achievable rate region for the genie-aided cognitive radio channel is obtained using the celebrated HanKobayashi jointly decoding strategy for the interference channel and the Gel'fand-Pinsker coding scheme for channels with side information known at the transmitter. The achievable rate region is then simplified by Fourier-Motzkin elimination. The obtained achievable rate region (i) extends the Chong-Motani-Garg region for the interference channel to the cognitive channel and (ii) is a simplified description of the Devroye-Mitran-Tarokh rate region for the genie-aided cognitive radio channel. © 2009 IEEE
A novel semi-supervised clustering algorithm for finding clusters of arbitrary shapes
, Article 13th International Computer Society of Iran Computer Conference on Advances in Computer Science and Engineering, CSICC 2008, Kish Island, 9 March 2008 through 11 March 2008 ; Volume 6 CCIS , 2008 , Pages 876-879 ; 18650929 (ISSN); 3540899847 (ISBN); 9783540899846 (ISBN) ; Bagheri Shouraki, S ; Sharif University of Technology
2008
Abstract
Recently, several algorithms have been introduced for enhancing clustering quality by using supervision in the form of constraints. These algorithms typically utilize the pair wise constraints to either modify the clustering objective function or to learn the clustering distance measure. Very few of these algorithms show the ability of discovering clusters of different shapes along with satisfying the provided constraints. In this paper, a novel semi-supervised clustering algorithm is introduced that uses the side information and finds clusters of arbitrary shapes. This algorithm uses a two-stage clustering approach satisfying the pair wise constraints. In the first stage, the data points...
New Achievable Rates In Frequency Hopped Spread Spectrum Systems
, M.Sc. Thesis Sharif University of Technology ; Marvasti, Farrokh (Supervisor)
Abstract
In this dissertation, we investigate the frequency hopped spread spectrum systems which are extensively used in many communication systems. We derive the capacity region of Synchronous Frequency Hopped Multiple Access (FHMA) channels (for any kind of noisy or nonselective fading environment) by using the side information which exists in the multi‐user detection. We assume that random hopping patterns are used by all the transmitters, and the common receiver knows the hopping patterns. We also compute the capacities of FHMA with and without power control for AWGN and noiseless MFSK (in particular BFSK) modulated systems and compare the ...