Sharif Digital Repository

Graceful labeling is one of the best known labeling methods of graphs. Despite the large number of papers published on the subject of graph labeling, there are few particular techniques to be used by researchers to gracefully label graphs. In this paper, first a new approach based on the mathematical programming technique is presented to model the graceful labeling problem. Then a “branching method” is developed to solve the problem for special classes of graphs. Computational results show the efficiency of the proposed algorithm for different classes of graphs. One of the interesting results of our model is in the class of trees. The largest tree known to be graceful has at most 27 vertices... 

Graceful labeling is one of the best known labeling methods of graphs. Despite the large number of papers published on the subject of graph labeling, there are few particular techniques to be used by researchers to gracefully label graphs. In this paper, first a new approach based on the mathematical programming technique is presented to model the graceful labeling problem. Then a “branching method” is developed to solve the problem for special classes of graphs. Computational results show the efficiency of the proposed algorithm for different classes of graphs. One of the interesting results of our model is in the class of trees. The largest tree known to be graceful has at most 27 vertices... 

Gastpar and Vetterli named the adhoc networks with one randomly selected source-destination pair as relay networks and they suggested using arbitrary network coding in order to increase the overall efficiency Here, the relay network is investigated with two relays and no interference and a new achievable rate is obtained using a new network coding (decodeand-broadcast). The obtained achievable rate (i) gives the lower bound for the general relay channel, obtained by Cover and El Gamal, but with slight difference due to no interference assumption at the receiver (ii) includes the one relay rates of a two-level relay channel studied by Gupta and Kumar using point to point coding, (iii)... 

This study presents and analyses a novel joint detection and parameters estimation of multiple targets using a co-located multiple input/multiple output radar with moving platform, in the presence of clutter and background noise. A notable feature of the proposed approach is that clutter cancellation is independent of received data. Moreover, to decrease the computational load, the authors propose to perform the target detection and parameters estimation by directly processing on the compressive measurements as opposed to Nyquist samples. © The Institution of Engineering and Technology  

It is known that discrete scale invariance leads to log-periodic corrections to scaling. We investigate the correlations of a system with discrete scale symmetry, discuss in detail possible extension of this symmetry such as translation and inversion, and find general forms for correlation functions. © 2003 Published by Elsevier Science B.V  

Carbon-based sensors are attractive because of their excellent sensing capability. In this paper, we propose a new approach to analytically model the sensitivity of these devices based on graphene. The model relies on the surface potential and current of the device. For the first time, we included ionization in the modelling and examined the importance of this effect. In order to validate the model, the results are compared with experimental data from a fabricated device  

Due to the growing demand for large memories, using emerging technologies such as Phase Change Memories (PCM) are inevitable. PCM with appropriate scalability, power consumption and multiple bits per cell storage capability is a probable candidate for substituting DRAM. Although storing multiple bits per cell seems to be a rational response to large memory demands, there is a significant problem to achieve this goal. Resistance drift problem is an important reliability concern that is coupled to a multi-level cell PCM (MLC PCM) memory system. In this paper, we propose a memory system architecture that, by exploiting the benefits of compression, converts resistance drift prone blocks to drift... 

In this paper, we propose a reconfigurable NoC in which a customized topology for a given application can be implemented. In this NoC, the nodes are grouped into some clusters interconnected by a reconfigurable communication infrastructure. The nodes inside a cluster are connected by a fixed topology. From the traffic management perspective, this structure benefits from the interesting characteristics of the mesh topology (efficient handling of local traffic where each node communicates with its neighbors), while avoids its drawbacks (the lack of short paths between remotely located nodes). We then present a design flow that maps the frequently communicating tasks of a given application into... 

This article is focused on developing an Energy Service Company (ESCO) risk assessment model for use by energy savings certificates (ESC) market regulators. This model enables market regulators to determine the appropriate point in time for ESCOs to sell their certificates with the aim of minimizing risk as well as maximizing economic gain yet remain motivated for reducing the cost of energy efficiency technologies. To this end, the interactions between an ESCO and other parties (such as suppliers) in the market in addition to the principles of the energy efficiency performance contract are taken into consideration. Then, appropriate probability distributions have been fitted to the... 

In this paper, a parallel algorithm for computing the roots of a given polynomial of degree n on a ring of processors is proposed. The algorithm implements Durand-Kerner's method and consists of two phases: initialisation, and iteration. In the initialisation phase all the necessary preparation steps are realised to start the parallel computation. It includes register initialisation and initial approximation of roots requiring 3n - 2 communications, 2 exponentiation, one multiplications, 6 divisions, and 4n - 3 additions. In the iteration phase, these initial approximated roots are corrected repeatedly and converge to their accurate values. The iteration phase is composed of some iteration... 

In this paper, a parallel algorithm for computing the roots of a given polynomial of degree n on a ring of processors is proposed. The algorithm implements Durand-Kerner's method and consists of two phases: initialization, and iteration. In the initialization phase all the necessary preparation steps are realized to start the parallel computation. It includes register initialization and initial approximation of roots requiring 3n-2 communications, 2 exponentiation, one multiplications, 6 divisions, and 4n-3 additions. In the iteration phase, these initial approximated roots are corrected repeatedly and converge to their accurate values. The iteration phase is composed of some iteration... 

Although several analytical models have been proposed in the literature for binary n-cubes with deterministic routing, most of them have not included the effects of virtual channel multiplexing on network performance. The only mathematical model for deterministic wormhole routing in hypercubes with virtual channels was proposed in [Y. Boura, Design and Analysis of Routing Schemes and Routers for Wormhole-routed Mesh Architectures, Ph.D. Thesis, Department of Computer Science and Engineering, Pennsylvania State University, 1995] which uses complex combinatorial analysis with a computation time of O(N = 2n) for an n-dimensional hypercube. This paper proposes a new and simple analytical model... 

The mesh structure has been used as the underlying topology for many practical multicomputers, and has been extensively studied in the past. In this paper, we investigate some topological properties of meshes. In particular, we study the problem of finding the number of nodes located at a given distance from a given node (surface area) and the number of nodes located within a given distance from a given node (volume), and have derived some expressions calculating these numbers