Sharif Digital Repository

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  

In this paper, nano/microstructured-conducting polypyrrole has been prepared on Cu/Au interdigital electrode surfaces by using constant potential amperometry technique. The Fe(II) ions were used as catalyst and X = ClO4 -, pTs-, Cl-, TCA-, DS-, DBS- was implemented as anion dopants. The morphologies of the films were investigated by field emission scanning electron microscope. A remarkable dependence was observed between the type of anion dopant and the morphology of polypyrrole (PPy). The sensing behavior of the PPy-X sensor has been studied toward acetone, methanol, ethanol, 1-propanol, 2-propanol, nitromethane, propylamine, pyridine, and gas mixtures of aliphatic alcohols. The responses... 

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  

Connections have very important role in pre-cast concrete structures, especially in seismic zones, and grout connections increase strength and resistance of pre-cast concrete structures for lateral forces. High performance grout connections (HPGC) provide new opportunities to design cost-effective pre-cast concrete structures. HPGC have been proposed to decrease cost of insulation, erection and crane cost of pre-cast concrete structures and to overcome weakness of traditional pre-cast concrete structure connections .This research focuses on properties of grout materials properties which produced in Iran and the effect of propylene fiber on the performance of grout connection. In the first... 

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  

We have investigated the water permeation through carbon nanotube (CNT) membranes as a model of peptide nanotube channels (PNCs). The effect of different charge configured CNTs which tailored based on some artificial ion channels on the water permeation through the channels have been studied. In addition, the temperature dependence of the permeation has been investigated. We have found that there is a jump in the permeation which is somehow related to the characteristics of each channel and the temperature of this permeation jump changes according to the channel configuration. Our investigation on the channels shows that the temperature at which the permeation jump occurs is related to the... 

Original scientific paper Developing a model for citizens' satisfaction with public services is one of the effective factors for improvement of service quality. In recent years, many studies have been carried out to identify a model for citizens' satisfaction with public sector services. In the structure of the presented models in the literature, one of the most important issues regarding organizations giving public services is identification of service scopes that have the most impact on citizens' satisfaction. This paper aims to develop a model to identify citizens' satisfaction status with public services. To do so, first, key factors influencing citizens' satisfaction with public... 

We study the variety of Löb algebras, the algebraic structures associated with Formal Propositional Calculus. Among other things, we show that there exist only two maximal intermediate logics in the lattice of intermediate logics over Basic Propositional Calculus. We introduce countably many locally finite sub-varieties of the variety of Löb algebras and show that their corresponding intermediate logics have the interpolation property. Finally, we characterize all chain basic algebras with empty set of generators, and show that there are continuum many such chain basic algebras  

Cryogenic technologies not only improve the performance of interconnects but also the performance of transistors and consequently drivers and repeaters. Although in cryogenically cooled integrated circuits the local temperature of interconnects and transistors may be as low as 50 K, it may easily reach to 600 K in high-temperature chips. In this brief, we investigated the impact of temperature on the delay of local, intermediate, unit-repeater-inserted (URI), and cascaded repeater-inserted (CRI) global copper interconnects for minimum technology node with available transistor model (32-nm technology). Our results show that temperature variation of driver resistance could change the delay of... 

This paper presents a design methodology for class-J monolithic microwave integrated circuit (MMIC) power amplifiers (PAs). Theoretical derivations of optimum load impedances, output power, efficiency, and maximum bandwidth are described in presence of nonlinear drain-source resistance of transistors (RDS). A procedure is developed for ideal transistor sizing where transistors are concurrently stabilized and sized to achieve the maximum power-added efficiency (PAE). A 3.5-7 GHz, 0.5-W class-J PA is implemented in a 0.1-μm AlGaAs-InGaAs pHEMT technology to check the accuracy of the proposed approach. With chip dimensions of 1.57 × 1.29 mm2, the PA achieves 56% average PAE over the frequency... 

The performance of gigascale integration chips improves by cryogenic technologies such as subambient cooling. In these conditions, interconnects may perform at temperatures as low as 50 K. However, the local temperature of interconnects could easily be as high as 600 K at high-temperature chips. In this brief, we investigated the impact of temperature on delay of local, intermediate, and global interconnects of International Technology Roadmap for Semiconductors Node 2024. This is done for different values of interconnect width and length, nanotube diameter, and percentage of metallic carbon nanotubes (CNTs) in a grown bundle. Results are compared with those of copper counterpart. We showed... 

With increasing use of e-banking system in Iranian banking sector, ignoring the issue of fraud in the system will be very costly for banks and e-banking customers. Fraud in e-banking is due to some security problems (such as weakness in access control systems and inadequate internal control). So, identifying success factor in fraud prevention in ebanking can be useful for e-banking system developers to improve these systems security. In this paper we have tried to identify and rank these success factors for fraud prevention in e-banking systems. For this purpose, we first review the literature to find potential factors, then identified factors were weighted by using fuzzy group multi... 

We study basic propositional logic (BPC) augmented with the law of the weak excluded middle (WEM), i.e. BPW = BPC+WEM. We show that the variety of the algebraic models of BPW is canonical, and its Kripke completeness is proved via cononicity. Moreover, it is also proved that BPW has the finite model property and is decidable. It is shown that BPC and BPW have the same behaviour on the ˔-free formulas and that CPC and BPW have the same behaviour on the negated formulas. © The Author(s) 2018. Published by Oxford University Press. All rights reserved