Sharif Digital Repository

The conventional delay-line discriminator method for phase noise measurement is modified to achieve better sensitivity. In the proposed technique, to decrease delay-line loss, the under-test oscillator's microwave frequency is down-converted by another oscillator, and delay-line is implemented in the IF range. Full validation of the technique is presented. In adition, we experimentally demonstrate that system sensitivity is considerably improved compared to the conventional method  

This paper presents a novel Cyber-Physical System (CPS) equipped with an advanced Distributed Model Predictive Control (DMPC) method with reduced order computational complexity, zero steady-state error, reduced start-up energy consumption and improved transient response for the optimal heating-cooling of buildings. The satisfactory application of this method for the optimal heating-cooling of a large-scale (6-story) building with 40 rooms is illustrated. Smart Industrial Internet of Things (IIoT) -based thermostats, a gateway and a general Quadratic Programming (QP) solver are developed. Using this hardware set-up, the simulation results for the 6-story building are verified in a small scale... 

This paper presents a novel Cyber-Physical System (CPS) equipped with an advanced Distributed Model Predictive Control (DMPC) method with reduced order computational complexity, zero steady-state error, reduced start-up energy consumption and improved transient response for the optimal heating-cooling of buildings. The satisfactory application of this method for the optimal heating-cooling of a large-scale (6-story) building with 40 rooms is illustrated. Smart Industrial Internet of Things (IIoT) - based thermostats, a gateway and a general Quadratic Programming (QP) solver are developed. Using this hardware set-up, the simulation results for the 6-story building are verified in a small... 

The integral equation technique, in combination with the method of moments, is widely used for treating the electromagnetic scattering from periodic rough surfaces. This method, however, requires the computation of a kernel (a periodic Green's function) that consists of a slowly converging infinite series of conventional Green's functions. To accelerate the convergence of this series, different methods have been proposed in literature. In this paper, we use a complex image (CI) technique to find a closed-form expression for the periodic Green's function, which is then used to analyze the electromagnetic scattering from arbitrary periodic rough surfaces. The resulting CI Green's function... 

Eelectromagnetic analysis of periodic structures is important in the electromagnetic theory. Among them, the electromagnetic wave scattering analysis from rough surfaces is of importance due to both theoretical and practical points of view. For slow variation periodic surfaces the solution can be obtained under the Rayleigh hypothesis in terms of Floquet modes [1]. Integral equation approaches in combination with the method of Moments are among the most frequently used in the solution of scattering problems related to periodic surface due to their flexibility in modeling different geometries [2-3]. Due to slowly convergence of infinite series periodic Green's function, these methods need... 

Purpose. Drug release from nanosystems at the sites of either absorption or effect biophase is a major determinant of its biological action. Thus, in vitro drug release is of paramount importance in gaining insight for the systems performance in vivo. Methods. A novel in vitro in vivo correlation, IVIVC, model denoted as double reciprocal area method was presented and applied to 19 drugs from 55 nano formulations with total 336 data, gathered from literature. Results. The proposed model correlated the in vitro with in vivo parameters with overall error of 12.4 ± 3.9%. Also the trained version of the model predicted the test formulations with overall error of 15.8 ± 3.7% indicating the... 

We study two-dimensional (2D) hole arrays drilled into a perfect conductor slab covered with a graphene sheet. Such arrays support the extraordinary transmission of electromagnetic waves and allow tunability via graphene properties. We investigate the effect of graphene on transmission spectra by proposing an accurate analytical circuit model for the structure, where the graphene contributes an admittance component at the interface. The model demonstrates how extraordinary transmission can be tuned via the graphene conductivity. We study the free-standing structure, where the hole array is covered by a graphene sheet on both sides of the conductor slab, and a substrate-bound hole array... 

We study two-dimensional (2D) hole arrays drilled into a perfect conductor slab covered with a graphene sheet. Such arrays support the extraordinary transmission of electromagnetic waves and allow tunability via graphene properties. We investigate the effect of graphene on transmission spectra by proposing an accurate analytical circuit model for the structure, where the graphene contributes an admittance component at the interface. The model demonstrates how extraordinary transmission can be tuned via the graphene conductivity. We study the free-standing structure, where the hole array is covered by a graphene sheet on both sides of the conductor slab, and a substrate-bound hole array... 

This paper presents a novel approach for designing dual-band absorbers based on graphene and metallic metasurfaces for terahertz and mid-infrared regimes, respectively. The absorbers are composed of a 2D array of square patches deposited on a dielectric film terminated by a metal plate. Using an analytical circuit model, we obtain closed-form relations for different parameters of the structure to achieve the dual-band absorber. Two absorption bands with an obtained absorptivity of 98% at 0.53 and 1.53 THz for the graphene-based structure and 7 and 25 THz for the metallic-based case are achieved. We demonstrate that the graphene-based absorber remains as the dual band for a wide range of the... 

Novel types of highly swelling hydrogels (superabsorbent) were prepared by grafting crosslinked poly acrylic acid-co-2-hydroxyethylmetacrylate (PAA-co-HEMA) chains onto starch through a free radical polymerization method. The effect of grafting variables (i.e., concentration of methylenebisacrylamide (MBA), acrylic acid/2-hydroxy methymetacrylate (AA/HEMA) weight ratio, ammonium persulfate (APS), starch, neutralization percent, were systematically optimized to achieve a hydrogel with a maximum swelling capacity. The superabsorbent (SAP) formation was confirmed by Fourier transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM). The controlled-release behavior of... 

Despite their potential applications, a limited number of studies for synthesizing vertical MoS2 nanoflakes especially via CVD have been reported so far, which generally involve tedious complex- and/or multi-step growth processes. In this study, direct synthesis of vertical MoS2 nanoflakes grown on the SiO2/Si substrate during a rapid sulfidation process by CVD method has been reported. Material characterization was performed using Raman spectroscopy, XRD and FE-SEM. The XRD results indicated the dominant phase of 2H–MoS2 within the synthesized layers. The characteristic distance between the two dominant peaks of E1 2g and A1g in the Raman spectra confirms the multi-layered structure for... 

I present an in-depth review of the trends and the directions taken by researchers worldwide in optical code-division multiple-access (OCDMA) systems. I highlight those trends and features that I believe are essential to the successful introduction of various OCDMA techniques in communication systems and data networks in the near future. In particular I begin by giving a comprehensive review of the construction of optical orthogonal codes (OOCs). Specifically I discuss the recently developed algorithms that are based on matrix algebra, which simplify and enhance the efficiencies of algorithms in OOC generation. In communication systems studies I first focus on and discuss various OCDMA... 

Energy consumption and performance metrics have become critical issues for scheduling parallel task-based applications in high-performance computing systems such as cloud datacenters. The duplication and clustering strategy, as well as Dynamic Voltage Frequency Scaling (DVFS) technique, have separately been concentrated on reducing energy consumption and optimizing performance parameters such as throughput and makespan. In this paper, a dual-phase algorithm called EATSDCD which is an energy efficient time aware has been proposed. The algorithm uses the combination of duplication and clustering strategies to schedule the precedence-constrained task graph on datacenter processors through DVFS.... 

Energy consumption and performance metrics have become critical issues for scheduling parallel task-based applications in high-performance computing systems such as cloud datacenters. The duplication and clustering strategy, as well as Dynamic Voltage Frequency Scaling (DVFS) technique, have separately been concentrated on reducing energy consumption and optimizing performance parameters such as throughput and makespan. In this paper, a dual-phase algorithm called EATSDCD which is an energy efficient time aware has been proposed. The algorithm uses the combination of duplication and clustering strategies to schedule the precedence-constrained task graph on datacenter processors through DVFS.... 

John Archibald Wheeler is one of the staunchest advocates of the idea that information is more fundamental than anything else in physics. In this paper, we examine the status of this idea summarized in Wheeler’s slogan ‘it from bit’ in the context of Bohmian Mechanics and spontaneous collapse models. We will argue that any question about the status of ‘it from bit’ crucially depends on the particular interpretation of these theories one favors. © 2019, Springer Nature B.V  

John Archibald Wheeler is one of the staunchest advocates of the idea that information is more fundamental than anything else in physics. In this paper, we examine the status of this idea summarized in Wheeler’s slogan ‘it from bit’ in the context of Bohmian Mechanics and spontaneous collapse models. We will argue that any question about the status of ‘it from bit’ crucially depends on the particular interpretation of these theories one favors. © 2019, Springer Nature B.V  

According to Zeilinger’s information interpretation of quantum mechanics ‘the distinction between reality and our knowledge of reality, between reality and information, cannot be made. They are in a deep sense indistinguishable’. This is what we call Zeilinger’s thesis. This thesis has been criticized as a lapse into ‘informational immaterialism’ and amounting to nothing more than a tautology. However, we will argue that this criticism is based on a pre-Kantian view of reality, namely metaphysical realism which could be questioned on the basis of Putnam’s arguments. Furthermore, it will be argued that to understand Zeilinger’s thesis one should abandon the pre-Kantian perspective of... 

Noise interference and data loss are two major problems that affect the processing results of image data transmission and storage. Restoration of the lost information of an image based on the existing information is the essence of inpainting. In this paper a new algorithm based on Sample and Hold interpolation and Iteration is proposed for reconstructing damaged images from existing regions and is compared to some other methods. The experimental results show the superiority of the visual quality and PSNR performance of the proposed method. It is observed that this approach can efficiently fill in the holes with visually plausible information