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khosravi-farsani--mostafa
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Two-way writing on dirty paper
, Article IEEE Communications Letters ; Volume 15, Issue 7 , July , 2011 , Pages 689-691 ; 10897798 (ISSN) ; Rostami, M ; Sharif University of Technology
2011
Abstract
In this paper, the Two-Way Channel (TWC) with noncausal Channel State Information (CSI) is investigated. For the discrete memoryless channel an achievable rate region is derived. Then by extending the result to the Gaussian TWC with additive interference noise, it is shown that the capacity region of the latter channel is the same as the capacity when there is no interference, i.e., a two-way version of Costa's writing on dirty paper problem is established
Capacity bounds for multiuser channels with non-causal channel state information at the transmitters
, Article 2011 IEEE Information Theory Workshop, ITW 2011 ; 2011 , Pages 195-199 ; 9781457704376 (ISBN) ; Marvasti, F ; Sharif University of Technology
2011
Abstract
In this paper, capacity inner and outer bounds are established for multiuser channels with Channel State Information (CSI) known non-causally at the transmitters: The Multiple Access Channel (MAC), the Broadcast Channel (BC) with common information, and the Relay Channel (RC). For each channel, the actual capacity region is also derived in some special cases. Specifically, it is shown that for some deterministic models with non-causal CSI at the transmitters, similar to Costa's Gaussian channel, the availability of CSI at the deterministic receivers does not affect the capacity region
Achievable rate regions for dirty tape channels and "joint writing on dirty paper and dirty tape"
, Article 2010 IEEE Information Theory Workshop, ITW 2010 - Proceedings, 30 August 2010 through 3 September 2010 ; 2010 ; 9781424482641 (ISBN) ; Akhbari, B ; Aref, M. R ; Sharif University of Technology
2010
Abstract
We consider the Gaussian Dirty Tape Channel (DTC) Y=X+S+Z, where S is an additive Gaussian interference known causally to the transmitter. The general expression maxPU, f(.), X=f(U,S) I(U;Y) is proposed for the capacity of this channel. For linear assignment to f(.), i.e., X=U-βS, this expression leads to the compensation strategy proposed previously by Willems to obtain an achievable rate for the DTC. We show that linear assignment to f(.) is optimal under the condition that there exists a real number β* such that the pair (X+β*S, U) is independent of the interference S. Furthermore, by applying a time-sharing technique to the achievable rate derived by linear assignment to f (.), an...
The capacity region of a class of relay-broadcast channels and relay channels with three parallel unmatched subchannels
, Article ISITA/ISSSTA 2010 - 2010 International Symposium on Information Theory and Its Applications, 17 October 2010 through 20 October 2010 ; October , 2010 , Pages 818-823 ; 9781424460175 (ISBN) ; Akhbari, B ; Aref, M. R ; Sharif University of Technology
2010
Abstract
The Partially Cooperative Relay-Broadcast Channel (PC-RBC) is a generalization of Relay Channel in which the relay node decodes its own private message. In this paper, we introduce a class of parallel PC-RBCs with three unmatched subchannels, in which the first component of the channel is assumed to be degraded, the second to be orthogonal and the third to be deterministic. We characterize the capacity region of this channel for the case where the source sends a private message for each of the users. We also investigate a class of parallel relay channels with three unmatched subchannels, in which the first component of the channel is degraded, the second is orthogonal and the third is...
Oscillators in Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Fotouhi Firouzabad, Morteza (Supervisor)
Abstract
In this Thesis, we investigate the Modeling of Oscillator Neural Networks. Let Oscillators are coupled to each other Weakly. agood way to use Phase Model to describe each Oscillator. Then provide specific Examples to see the nesseceryConditions forExsistence and Stability of Synchrony and desyncrony
Analysis of Dimensions, Objective and Implementation of Knowledge Management in Production Institutes
, M.Sc. Thesis Sharif University of Technology ; Mostafavi, Mostafa (Supervisor)
Abstract
The increasing significance and deployment of knowledge management(KM) is the main reason for selecting the topic of this research. This research tries to analyse the dimensions and KM implementation methods in press section of maintenance department in Saipa company. This study has a qualitative approach and the method is based on a case study. Data has been collected by questionnaires. Two questionnares have been provided in this research and distributed among different staff of press section in maintenance department. The concept of knowledge management maturity is applied and the goal of first questionnaire is based on this concept. The level of KM maturity is assessed via this...
Cooperative relay-broadcast channels with causal channel state information
, Article 2009 IEEE International Symposium on Information Theory, ISIT 2009, Seoul, 28 June 2009 through 3 July 2009 ; 2009 , Pages 1174-1178 ; 21578102 (ISSN); 9781424443130 (ISBN) ; Akhbari, B ; Mirrnohseni, M ; Aref, M. R ; Sharif University of Technology
2009
Abstract
In this paper, we consider partially and fully cooperative state-dependent relay broadcast channels with perfect causal Channel State Information (CSI). For these two channels, we study three different situations: 1) both the source and the relay nodes have access to perfect CSI, 2) perfect CSI is only known to the relay nodes, 3) perfect CSI is only available at the source node. In each situation we obtain the capacity region for a degraded version of the channel. Our work subsumes previously obtained results for the degraded broadcast and relay channels with perfect causal CSI. © 2009 IEEE
The capacity region of the parallel partially cooperative relay broadcast channel with unmatched degraded subchannels
, Article 2009 IEEE International Symposium on Information Theory, ISIT 2009, Seoul, 28 June 2009 through 3 July 2009 ; 2009 , Pages 189-193 ; 21578102 (ISSN); 9781424443130 (ISBN) ; Mirmohseni, M ; Akhbari, B ; Firouzi, H ; Aref, M. R ; Sharif University of Technology
2009
Abstract
We investigate the parallel partially cooperative relay broadcast channel with unmatched degraded subchannels. We characterize the capacity region of this channel in the general setting that, transmitter sends a common message for both users and a private message for each of them. Our achievability result is based on the choosing appropriate parameters for the general achievable rate region of partially cooperative relay broadcast channel. We provide a converse proof for this achievable region as well, which establishes the capacity region.© 2009 IEEE
Inventory-Routing Problem with Deliveries and Pickups
, M.Sc. Thesis Sharif University of Technology ; Shavandi, Hassan (Supervisor)
Abstract
In today’s industrial world, firms’ focus on production only, embedded in forward supply chains is not acceptable. Environmental crises have drawn public attention to the concept of Sustainability, and government regulations are pushing firms to taking the responsibility of their wastes. These have led to manufacturers’ tendency towards collecting returns from their customers in order to use them in remanufacturing processes embedded in Reverse Supply Chains. Besides, inventory policies compatible with appropriate flows of information is widely being used, out of which is the Vendor-Managed Inventory policy. These reasons clarify the importance of research and academic work into the field of...
Numerical investigation of gaseous hydrogen and liquid oxygen combustion under subcritical condition
, Article Energy and Fuels ; Volume 33, Issue 9 , 2019 , Pages 9249-9271 ; 08870624 (ISSN) ; Ghasempour Farsani, A ; Farshchi, M ; Sharif University of Technology
American Chemical Society
2019
Abstract
This study is on combustion modeling of gaseous hydrogen and cryogenic liquid oxygen at the subcritical condition for the well-known Mascotte laboratory combustor. The proposed strategy relies on the hybrid Eulerian-Lagrangian framework in which the continuous phase is evaluated by Reynolds Average Navier-Stokes (RANS) equations and the quick discretization method. The dispersed phase of the combustion field is evaluated by the Discrete Phase Method (DPM). The Eddy Dissipation Concept (EDC) has been performed for combustion-turbulence interaction modeling. Effects of the turbulence model, chemical kinetic mechanism, equation of state, and inlet momentum jet flux are investigated in terms of...
Effect of the shear loading direction on shear behavior of rock and finding new empirical method for determining JRC by fractal dimension
, Article Annual Conference of the Canadian Society for Civil Engineering 2007: Where the Road Ends, Ingenuity Begins, Yellowknife, NT, 6 June 2007 through 9 June 2007 ; Volume 1 , 2007 , Pages 259-267 ; Sadaghiani, M. H ; Askari, M ; Khosravi, M ; Sharif University of Technology
2007
Abstract
Effect of different conditions on shear behaviour of rock has been investigated by various researchers. As known, in larger scale the continuity of the rock material is interrupted by separated planes such as bedding planes, faults, shear zones, closure and the behaviour converts to be inelastic and anisotropic. Generally, discontinuities appear repeatedly in more than one preferential direction, creating a three dimensional structure, reducing its stiffness and shear strength as mechanical effects and increasing its transport velocity associated with discontinuity flow as hydraulic effects. They also make rock behavior more complex and different compared to the behavior of soil. According...
Cooperative relay broadcast channels with partial causal channel state information
, Article IET Communications ; Volume 5, Issue 6 , 2011 , Pages 760-774 ; 17518628 (ISSN) ; Khosravi Farsani, R ; Aref, M. R ; Sharif University of Technology
2011
Abstract
The authors consider 'partially' and 'fully cooperative' state-dependent relay broadcast channels (RBCs), where partial channel state information (CSI) is available at the nodes causally. First, the authors derive an achievable rate region for general discrete memoryless partially cooperative RBC (PC-RBC) with partial causal CSI, by exploiting superposition coding at the source, decode-and-forward scheme at the relay and Shannon's strategy at the source and the relay. Then, they establish the capacity region of the discrete memoryless physically degraded PC-RBC with partial causal CSI. They also characterise the capacity region of discrete memoryless PC-RBC with feedback and partial causal...
Multiple relay channels with delays: with and without side information
, Article GLOBECOM - IEEE Global Telecommunications Conference2009 ; Article number 5426043 , 2009 ; 9781424441488 (ISBN) ; Khosravi Farsani, R ; Aref, M. R ; Sharif University of Technology
2009
Abstract
In this paper the Multiple Relay Channels (MRC) with delays, with and without channel state information (CSI) are investigated from an information theoretic point of view. For the MRC 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 the MRC without-delay where the relays have access to the present received symbols in addition to the past symbols, the capacity of the degraded channel is established using Shannon's strategy for the channels with side information. Then we introduce the state dependent MRC with unlimited look ahead and derive a lower bound on the...
Self-healing polymers containing nanomaterials for biomedical engineering applications: a review
, Article Polymer Composites ; Volume 44, Issue 10 , 2023 , Pages 6869-6889 ; 02728397 (ISSN) ; Forghan Tarigheh, F ; Eslami Farsani, R ; Sharif University of Technology
John Wiley and Sons Inc
2023
Abstract
Materials that can recover the function of lost or damaged parts, called self-healing materials, have attracted attention due to their wide usage in different fields such as water refinery, coatings, robotics, and especially, biomedical applications. Depending on whether the self-healing component is added to the polymer or is inherent to the polymeric matrix, the self-healing properties of the polymeric materials can be classified into extrinsic and intrinsic self-healing. Hydrogels are one of the most used polymers in self-healing applications for various purposes, including tissue engineering, drug delivery, etc. Nanoparticles can endow some essential features to hydrogels, such as...
The capacity region of p-transmitter/q-receiver multiple-access channels with common information
, Article IEEE Transactions on Information Theory ; Volume 57, Issue 11 , 2011 , Pages 7359-7376 ; 00189448 (ISSN) ; Khosravi Farsani, R ; Aref, M. R ; Marvasti, F ; Sharif University of Technology
2011
Abstract
This paper investigates the capacity problem for some multiple-access scenarios with cooperative transmitters. First, a general Multiple-Access Channel (MAC) with common information, i.e., a scenario where p transmitters send private messages and also a common message to q receivers and each receiver decodes all of the messages, is considered. The capacity region of the discrete memoryless channel is characterized. Then, the general Gaussian fading MAC with common information wherein partial Channel State Information (CSI) is available at the transmitters (CSIT) and perfect CSI is available at the receivers (CSIR) is investigated. A coding theorem is proved for this model that yields an...
Joint pilot power and pattern design for compressive OFDM channel estimation
, Article IEEE Communications Letters ; Volume 19, Issue 1 , November , 2015 , Pages 50-53 ; 10897798 (ISSN) ; Mashhadi, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
This letter investigates the deterministic design of pilot power and pattern for sparse channel estimation in OFDM systems based on minimizing the coherence of the DFT sub-matrix. It has been suggested that the pilot pattern forming a cyclic difference set (CDS) or almost difference set (ADS) is optimal. So, we proposed a deterministic procedure that jointly optimized for pattern and power of pilots as a solution. First, pilot patterns forming CDS/ADS were gathered through a search. Then, the power was numerically allocated to the different pilots from all the patterns. Finally, the pilot pattern and power pair leading to minimum coherence was selected from the available pairs. Simulation...
Shortest paths with single-point visibility constraint
, Article Scientia Iranica ; Volume 13, Issue 1 , 2006 , Pages 25-32 ; 10263098 (ISSN) ; Ghodsi, M ; Sharif University of Technology
Sharif University of Technology
2006
Abstract
In this paper, the problem of finding the shortest path between two points in the presence of single-point visibility constraints is studied, In these types of constraint, there should be at least one point on the output path from which a fixed viewpoint is visible. The problem is studied in various domains, including simple polygons, polygonal domains and polyhedral surfaces. The method is based on partitioning the boundary of the visibility region of the viewpoint into a number of intervals. This is done from the combinatorial structure of the shortest paths from the source and destination to the points on the boundary. The result for the case of simple polygons is optimal with O(n) time...
Query-point visibility constrained shortest paths in simple polygons
, Article Theoretical Computer Science ; Volume 389, Issue 1-2 , 2007 , Pages 1-11 ; 03043975 (ISSN) ; Ghodsi, M ; Sharif University of Technology
2007
Abstract
In this paper, we study the problem of finding the shortest path between two points inside a simple polygon such that there is at least one point on the path from which a query point is visible. We provide an algorithm which preprocesses the input in O (n2 + n K) time and space and provides logarithmic query time. The input polygon has n vertices and K is a parameter dependent on the input polygon which is O (n2) in the worst case but is much smaller for most polygons. The preprocessing algorithm sweeps an angular interval around every reflex vertex of the polygon to store the optimal contact points between the shortest paths and the windows separating the visibility polygons of the query...
Visiting a polygon on the optimal way to a query point
, Article 2nd International Frontiers in Algorithmics Workshop, FAW 2008, Changsha, 19 June 2008 through 21 June 2008 ; Volume 5059 LNCS , 2008 , Pages 245-251 ; 03029743 (ISSN); 3540693106 (ISBN); 9783540693109 (ISBN) ; Ghodsi, M ; Sharif University of Technology
2008
Abstract
We study a constrained version of the shortest path problem in polygonal domains, in which the path must visit a given target polygon. We provide an efficient algorithm for this problem based on the wavefront propagation method and also present a method to construct a subdivision of the domain to efficiently answer queries to retrieve the constrained shortest paths from a single-source to the query point. © 2008 Springer-Verlag Berlin Heidelberg
Shortest paths in simple polygons with polygon-meet constraints
, Article Information Processing Letters ; Volume 91, Issue 4 , 2004 , Pages 171-176 ; 00200190 (ISSN) ; Ghodsi, M ; Sharif University of Technology
2004
Abstract
We study a constrained version of the shortest path problem in simple polygons, in which the path must visit a given target polygon. We provide a worst-case optimal algorithm for this problem and also present a method to construct a subdivision of the simple polygon to efficiently answer queries to retrieve the shortest polygon-meeting paths from a single-source to the query point. The algorithms are linear, both in time and space, in terms of the complexity of the two polygons. © 2004 Elsevier B.V. All rights reserved