Sharif Digital Repository

In this paper we consider the content distribution to a set of mobile users interested in the same content. We use the concept of mobile clouds, which exploits cooperation between mobile terminals over the low-power short-range links. We propose, formulate and investigate the energy efficiency and delay of four realistic cooperative content delivery strategies. The derived results, through analysis of mathematical models and simulations, demonstrate around 65% to 95% energy saving gain in mobile cloud strategies compared to conventional multicasting. We also show that using mobile clouds, content distribution delay can be reduced for up to 85%  

In this paper, we propose and study a context-aware leader selection algorithm within the concept of mobile clouds. We deploy a dedicated Cooperative Control Server (CCS) to assist and manage the process of leader selection more efficiently. The proposed algorithm collects data regarding instantaneous conditions of Mobile Terminals (MTs) and their radio environment; and then computes and assigns a rank to each MT. The ranks calculated based on a combination of different context-related parameters and corresponding weighting factors, allow selecting the leader. Furthermore, the energy efficiency and stability of the selected leaders is investigated for different parameter values through... 

Crosstalk is the major limiting factor in DSL systems in terms of bit-rate or service coverage. Multiuser power control algorithms can be used to combat crosstalk degrading effects. The best ever known distributed power control solution is Iterative Water-filling (IWF). In this paper the performance of IWF in an ADSL system is considered in terms of offered rate-region and convergence speed. Then two novel modifications are proposed to accelerate convergence (usually 100-400%) without any performance loss. Therefore it suits better in practical applications, since each iteration needs re-initialization of the modem. © 2004IEEE  

Using multiple antenna transmitters and/or receivers is becoming a common method for improving spectral efficiency of wireless channels. The physical layer of the next generation of WLAN systems (802.11n) is based on a Multiple Input Multiple Output (MIMO) system which seems to be an efficient solution for defects which could occur in wireless channels. In this paper, we investigate an adaptive bit allocation method to feed the quantized channel state data back to the transmitting antennas, depending on the channel condition in a Multiple Input Single Output (MISO) scheme. We have proposed an adaptive bit allocation scheme with a significant performance improvement over the fixed bit... 

Introduction: B lymphocyte-induced maturation protein 1 (BLIMP1) encoded by the positive regulatory domain 1 gene (PRDM1), is a key regulator in T cell differentiation in mouse models. BLIMP1-deficiency results in a lower effector phenotype and a higher memory phenotype. Methods: In this study, we aimed to determine the role of transcription factor BLIMP1 in human T cell differentiation. Specifically, we investigated the role of BLIMP1 in memory differentiation and exhaustion of human T cells. We used CRISPR interference (CRISPRi) to knock-down BLIMP1 and investigated the differential expressions of T cell memory and exhaustion markers in BLIMP1-deficient T cells in comparison with... 

This paper characterizes the exact spatial Degrees of Freedom (DoF) region of the two-user multiple-input-multiple-output two-interfering multiple-access channels (2-IMACs), which models the uplink transmission in cellular networks, for three scenarios. The first scenario is the 2-IMAC without cognition, for which the achievability is generalized for more than two transmitters in each multiple-access channel. The two-user 2-IMACs' DoF regions are also derived for two different genie-aided cognition scenarios. Here, zero forcing by transmitters and interference alignment are studied in a network with more than two transmitters, whereas previous works dealt with two-transmitter networks. We... 

In this paper, we consider the problem of minimizing the uplink delays of users in a 5G cellular network. Such cellular network is based on a Cloud Radio Access Network (CRAN) architecture with limited fronthaul capacity, where our goal is to minimize delays of all users through an optimal resource allocation. Earlier works minimize average delay of each user assuming same transmit power for all users. Combining Pareto optimization and Markov Decision Process (MDP), we show that every desired balance in the trade-off among infinite-horizon average-reward delays, is achievable by minimizing a properly weighted sum delays. In addition, we solve the problem in two realistic scenarios;... 

Introduction: The application of doxorubicin (DOX) in cancer therapy has been limited due to its drug resistance and poor internalization. Graphene oxide (GO) nanostructures have the capacity for DOX delivery while promoting its cytotoxicity in cancer. Areas covered: The favorable characteristics of GO nanocomposites, preparation method, and application in cancer therapy are described. Then, DOX resistance in cancer, GO-mediated photothermal therapy, and DOX delivery for cancer suppression are described. Preparation of stimuli-responsive GO nanocomposites, surface functionalization, hybrid nanoparticles, and theranostic applications are emphasized in DOX chemotherapy. Expert opinion: GO... 

In this paper, a "Game Theory" approach for finding an optimal path in a "Wireless Sensor Network" is discussed. WSN is one of the most interesting research fields in the communication networks, and is the center of attention in recent years. In our model, a pricing and payment technique is presented to obtain an optimal path in a WSN by considering reliability, energy and traffic load. The proposed algorithm is able to find a path which improves network lifetime, load distribution and path reliability  

Integrating high spatial resolution of functional magnetic resonance imaging (fMRI) and high temporal resolution of electroencephalogram (EEG) is promising in simultaneous EEG and fMRI analysis, especially for epileptic patients. The EEG recorded inside an MR scanner is interfered with MR artifacts. In this article, we propose new artifact reduction approaches and compare them with the conventional artifact reduction methods. Our proposed approaches are based on generalized eigenvalue decomposition (GEVD) and median filtering. The proposed methods are applied on experimental simultaneous EEG and fMRI recordings of an epileptic patient. The results show significant improvement over... 

The wear-out of flash-based Solid-State Drives (SSDs) is a main concern that significantly affects their reliability. One major parameter that accelerates SSD wear-out is the number of write-cycles committed to flash chips. The number of write-cycles in SSD-based disk subsystem is highly dependent on the erasure code implemented in Redundant Array of Independent Disks (RAIDs). In this paper, we investigate the impact of erasure codes and the configuration of storage subsystems (i.e., the number of disks participated in the RAID array and stripe unit size) on the endurance of storage systems. The number of write-cycles is considered as a metric to evaluate the endurance of storage system. We... 

In this paper we present a method of localizing multiple wideband acoustic sources based on both signal attenuation pattern and delays in the reception of the signal. Moreover, an additional order of flexibility is added to the problem by considering the attenuation model as an unknown function with reasonable prior assumptions about its functional space. Such approach is capable of enhancing the localization performance compared to when only the signal attenuation data or the time delays are used. A cost function is then formed in terms of the sources locations and the attenuation model parameters. Having different types of unknowns in the cost function, convergence concerns, and the... 

Let G be a graph. It is well-known that G contains a proper vertex-coloring with χ(G) colors with the property that at least one color class of the coloring is a dominating set in G. Among all such proper vertex-coloring of the vertices of G, a coloring with the maximum number of color classes that are dominating sets in G is called a dominating-χ-coloring of G. The number of color classes that are dominating sets in a dominating-χ-coloring of G is defined to be the dominating-χ-color number of G and is denoted by dχ(G). In this paper, we prove that if G is a claw-free graph with minimum degree at least two, then dχ(G)≥2