Sharif Digital Repository

Fractional-pixel accuracy Motion Estimation (ME) has been shown to result in higher quality reconstructed image sequences in hybrid video coding systems. However, the higher quality is achieved by notably increased Motion Field (MF) bitrate and more complex computations. In this paper, new half-pixel block matching ME algorithms are proposed to improve the rate-distortion characteristics of low bitrate video communications. The proposed methods tend to decrease the required video bandwidth, while improving the motion compensation quality. The key idea is to put a deeper focus on the search origin of the ME process, based on center-bias characteristics of low bitrate video MFs. To employ the... 

Motion estimation at fractional-pixel accuracy results in higher quality video sequences. However, the higher quality is achieved by more computations and increased required motion field bitrates. In this paper, new half-pixel accuracy block matching-based motion estimation algorithms are proposed to improve the rate-distortion characteristics of low-bitrate video communications. The proposed methods especially tend to decrease the required video bandwidth, with no degradation in quality of reconstructed image sequences. The key idea is to put a deeper focus on the origin (zero motion) based on the center-bias characteristics of low bitrate video motion fields. The experimental results show... 

Motion estimation and compensation is an essential part of existing video coding systems. Compared to the widely used block-matching algorithms (BMA), the mesh-based motion estimation (MME) produces better subjective and objective qualified image sequences in many cases, especially at low bitrates. However, the iterative refinement step of the MME is computationally too expensive. In this paper, we propose a fast MME scheme, which adjusts its interpolation patterns to the motion features of image sequences to achieve higher quality reconstructed results. Experimental results show notable rate-distortion improvement over both the BMA and the conventional non-iterative MME schemes, especially... 

Stem cell therapy has been introduced as an emerging approach for injured tissue regeneration. This chapter addresses developing regenerative medicine techniques for controlling stem cell behavior. Recent studies have been reviewed and novel approaches have been divided into four main categories: 3D bioprinting, lithography, microfluidics, and electrospinning. Moreover, the impact of applied biophysical and/or biochemical cues to the designed scaffold on controlling stem cell activity has been discussed. The potential of using stem cells for various soft and hard tissue regenerations has been explored in different bioengineered scaffolds and the applied techniques for controlling stem cell... 

We consider the design of an optimal natural-gas network. Our proposed network contains two echelons, Town Broad Stations (TBSs), and consumers (demand zones). Here, our aim is a two-stage cost minimization. We first determine locations of the TBS so that the location-allocation cost is minimized. Then, we show how to distribute the flow of gas among the TBS minimizing the flow cost by using Minimum Spanning Tree (MST). A case study in Mazandaran Gas Company in Iran is made to assess the validity and effectiveness of our proposed model  

Background:: Since the cornea is responsible for transmitting and focusing light into the eye, injury or pathology affecting any layer of the cornea can cause a detrimental effect on visual acuity. Aging is also a reason for corneal degeneration. Depending on the level of the injury, conservative therapies and donor tissue transplantation are the most common treatments for corneal diseases. Not only is there a lack of donor tissue and risk of infection/rejection, but the inherent ability of corneal cells and layers to regenerate has led to research in regenerative approaches and treatments. Methods:: In this review, we first discussed the anatomy of the cornea and the required properties for... 

This paper introduces a new file manager to support multiple categorization. The proposed file manager is designed based on a subtle idea named Conceptual File Management (CFM). According to this approach, files are not contained by folders; nevertheless, each file can be a member of one or more folders (concepts). A prototype file manager is designed and implemented based on the new approach. Filtering by set operations and also manual concept selection improves retrieval of the files. CFM improves file system's clarity and avoids ambiguity and redundancy. As a result, it reduces the size of file system and enhances file access  

A new mixed-integer nonlinear programming model is presented for the time-dependent vehicle routing problem with time windows and intelligent travel times. The aim is to minimize fixed and variable costs, with the assumption that the travel time between any two nodes depends on traffic conditions and is considered to be a function of vehicle departure time. Depending on working hours, the route between any two nodes has a unique traffic parameter. We consider each working day to be divided into several equal and large intervals, termed as a time interval of traffic. Here, allowing for long distances between some of the nodes, travel time may take more than one time interval of traffic,... 

The arrival of the mobile phone and its rapid and widespread growth may well be seen as one of the most significant developments in the fields of communication and information technology over the past two decades. The aim of this study is to compare two hybrid multi-criteria decision-making (MCDM) approaches to evaluate the mobile phone options with respect to user’s preferences. Firstly, we identify the most desirable features influencing the choice of a mobile phone. This is realised through a survey conducted among the target group, the experiences of the telecommunication sector experts and the studies in the literature. Secondly, two MCDM methods are used in the evaluation procedure.... 

Image completion is an active subject in image and video processing, which deals with recovering the missing or removed parts of a given 2-D or 3-D data. Here, we present a method to efficiently build the multiresolution pyramid for a partially-missing image, by which, multiresolution image completion can be efficiently initialized and performed. Using this approach, we improve our previous algorithm for multiresolution image completion, especially when the inputs suffer spread missing areas. In comparison with the overall process of image completion, the computational and space complexity of the proposed method for building multiresolution pyramid is eligible. The obtained results of our... 

Nowadays, gasochromic Pd/WO3 coatings as optically switchable materials during H2 absorption have become more interesting due to their novel applications in smart windows and gas sensor devices. In this study, WO3 films were fabricated by Pulsed Laser Deposition (PLD) on glass substrates. Using an electroless method, Pd nanoparticles were deposited on the surface of the produced films. The effect of Pd growth time on coloring/bleaching rate was studied for different submerging times (1, 2, 5, 10, 15, 20 and 40 min). The best coloring/bleaching velocity was attained with a growth time of 2 min. The effect of growing time and growth feature of Pd particles was further studied using Scanning... 

In this paper, a multi-product inventory problem is investigated in which a retailer buys items from different suppliers based on their purchasing costs and defective rates. Due to the warehouse and staff constraints involved, the inventory cycle consists of two parts. The first part corresponds to a screening period in which a destructive testing acceptance-sampling plan is used to accept or reject a lot. The other part is for selling the items. In the screening period, a lot that is rejected is returned to the suppliers where another lot is claimed for substitution at no cost. Shortage occurs during the screening period and the defective items are sold at a lower price at the end of the... 

In this paper, a multi-product inventory problem is investigated in which a retailer buys items from different suppliers based on their purchasing costs and defective rates. Due to the warehouse and staff constraints involved, the inventory cycle consists of two parts. The first part corresponds to a screening period in which a destructive testing acceptance-sampling plan is used to accept or reject a lot. The other part is for selling the items. In the screening period, a lot that is rejected is returned to the suppliers where another lot is claimed for substitution at no cost. Shortage occurs during the screening period and the defective items are sold at a lower price at the end of the... 

Tin sulfide (SnS2) has recently attracted considerable attention due to its layered structure that may form two dimensional morphologies. It is an n-type semiconductor with band gap and electron affinity similar to CdS and In2S3; therefore can be regarded as an alternative for these materials in thin film solar cells. Here, we synthesis of SnS2 nanoparticles with different morphology in different ratio of water-ethanol mixed solution by solvothermal method, and observe that more ethanol leads to large sheet like morphologies, while water based synthesis results in very small nanosheets. A challenge in wet deposition of device-quality thin films of SnS2 is the requirement for highly dispersed... 

In this paper, a novel hard-output detection algorithm for the complex multiple-input multiple-output (MIMO) detectors is proposed, which results in a significant throughput enhancement, a near-ML performance, and an SNR-independent fixed-throughput. Moreover, a high-throughput VLSI implementation is proposed, which is based on a novel method of the node generation and sorting scheme. The proposed design achieves the throughput of 10Gbps in a 0.13 μ CMOS process, which is the highest throughput reported in the literature for both the real and the complex domains. Synthesis results in 90nm CMOS also show that the proposed scheme can achieve the throughput of up to 15Gbps. Moreover, the FPGA... 

A novel detection algorithm with an efficient VLSI architecture featuring efficient operation over infinite complex lattices is proposed. The proposed design results in the highest throughput, the lowest latency, and the lowest energy compared to the complex-domain VLSI implementations to date. The main innovations are a novel complex-domain means of expanding/visiting the intermediate nodes of the search tree on demand, rather than exhaustively, as well as a new distributed sorting scheme to keep track of the best candidates at each search phase. Its support of unbounded infinite lattice decoding distinguishes the present method from previous K-Best strategies and also allows its complexity... 

A novel ultra high-throughput detection algorithm with an efficient VLSI architecture for high-order MIMO detectors in the complex constellations is proposed. The main contributions include a new method for the node generation in complex-domain, pipelinable sorters, and a simple combinational circuit instead of the conventional multipliers, which makes the proposed architecture multiplication-free. The proposed design achieves an SNR-independent throughput of 13.3 Gbps at the clock frequency of 556 MHz in a 0.13 μm CMOS technology with a near ML performance. The implemented design consumes 90 pJ per detected bit with the initial latency of 0.3 μs. Also, the synthesis results in a 90 nm CMOS... 

Activated carbon beds are extensively used in sweetening units of natural gas refineries for the purification of contaminated amine solutions. Correlation of experimental adsorption data using an analytical isotherm equation is need to design an accurate activated carbon bed. In the present study, the adsorption of BTEX from Diethanolamine (DEA) solution by commercial and granular activated carbon (AC) were performed. The Langmuir, Freundlich and Sips isotherm models were used to describe the equilibrium data. The accuracy of the results obtained from the adsorption isotherm models was compared and the values for the regressed parameters were reported. The results show that the Freundlich... 

Abstract: 3D bioprinting technology is a promising approach for corneal stromal tissue regeneration. In this study, gelatin methacrylate (GelMA) mixed with corneal stromal cells was used as a bioink. The visible light-based stereolithography (SLA) 3D bioprinting method was utilized to print the anatomically similar dome-shaped structure of the human corneal stroma. Two different concentrations of GelMA macromer (7.5 and 12.5%) were tested for corneal stroma bioprinting. Due to high macromer concentrations, 12.5% GelMA was stiffer than 7.5% GelMA, which made it easier to handle. In terms of water content and optical transmittance of the bioprinted scaffolds, we observed that scaffold with... 

Electrodeposited composite and nanocomposite layers have attracted considerable attention as engineering coatings, due to their favourable tribological properties and corrosion resistance. Ni[sbnd]Co alloy matrix composite coatings are particularly significant due to their extensive and developing industrial applications. Ceramic nanoparticles are commonly incorporated into the Ni[sbnd]Co alloy matrix to further improve their properties, opening new windows for industrial applications. This review aims to comprehensively assess the influence of operating parameters (including the type of current control, plating bath conditions, particle loading and size) on the deposit properties....