Sharif Digital Repository

Twitter sentiment analysis, which often focuses on predicting the polarity of tweets, has attracted increasing attention over the last years, in particular with the rise of deep learning (DL). In this paper, we propose a new task: predicting the predominant sentiment among (first-order) replies to a given tweet. Therefore, we created RETwEET, a large dataset of tweets and replies manually annotated with sentiment labels. As a strong baseline, we propose a two-stage DL-based method: first, we create automatically labeled training data by applying a standard sentiment classifier to tweet replies and aggregating its predictions for each original tweet; our rationale is that individual errors... 

The term "vortex" refers to a region in a fluid where the flow spin around an axis line, which could be flat or curved. Vortices can twist, stretch, move, and interact in several situations, once they are formed. The angular and linear momentum, along with some energy and mass, are all noticeable in a rotating vortex. Descriptions of vortices developed in various flows include smoke rings, dust devils, cyclones, and the wind surrounding a tropical tornado. The existence of vortices in the natural environment makes it important for researchers to explore them when and wherever they are encountered. Magnetic field effects include numerous technical applications such as: B. Extraction of... 

A potential peculiarity of software systems is that a large number of soft-errors are inherently derated (masked) at the software level. The rate of error-deration may depend on the type of algorithms and data structures used in the software. This paper investigates the effects of the underlying algorithms of programs on the rate of error-deration. Eight different benchmark programs were used in the study; each of them was implemented by four different algorithms, i.e. divide-and-conquer, dynamic, backtracking and branch-and-bound. About 10,000 errors were injected into each program in order to quantify and analyze the error-derating capabilities of different algorithm-designing- techniques.... 

The current study demonstrates homogenous decorating of zinc oxide quantum dots (QDs) onto graphene oxide (GO) surface via simple chemical method. The AFM image exhibited that the prepared graphene was 0.8 nm thick and hence practically monolayer. Average size of the ZnO QDs was estimated by transmission electron microscopy around 3 nm. Instrumental and chemical analyses demonstrated formation of a strong bond between ZnO QDs and GO, through C-O-Zn and C-Zn bridges. The UV-visible spectra displayed that the introduction of graphene sheets to ZnO QDs resulted in higher absorption intensity of UV as well as widening of adsorption window toward visible light for ZnO-Graphene due to chemical... 

Soft-errors are increasingly considered as a major cause for computer system failures. Software techniques are used as cost-effective and flexible techniques to tolerate soft-errors but the introduced overhead is not acceptable in some safety-critical real-time systems. The identification of the program blocks and protecting only vulnerable blocks against soft-errors reduces the performance overhead. In this paper, we present a genetic algorithm to identify the vulnerable program blocks as well as the derating program blocks against soft-errors. Then, only vulnerable blocks are protected by some software-based soft-error tolerance techniques to achieve a lower performance and space overhead.... 

Biodegradable polymer/bioceramic nanocomposites are osteoconductive and can accelerate healing of bone tissue. In this research, silk fibroin (SF)/titanium dioxide (TiO2) nanocomposites were synthesized using different concentrations of TiO2 nanoparticles (0, 5, 10, 15 and 20 wt%). The SF/TiO2 nanocomposites were studied in terms of bioactivity and biocompatibility. The in vitro assessment of osteoblasts compatibility indicated that SF inclusion rendered nanocomposite biocompatible whereas presence of TiO2 nanoparticles allowed the cells to adhere and grow on nanocomposite surface and enhanced the bioactivity of the composite. © 2017, Taiwanese Society of Biomedical Engineering  

In this research, a web-based simulator is developed, which can be used for generating image sequences of moving spermatozoa cells. It can be used for assessment of multiple object tracking algorithms, especially Computer Aided Sperm Analysis (CASA) systems. The developed software has many useful parameters such as blurring images or adding noise and it also gives full control of sperm counts and types. To illustrate performance of the developed simulator, three parameters (spermatozoa population, standard deviation of Gaussian blur filter and noise intensity) have been swept and the results of three different multiple object tracking algorithms were compared as an application of this... 

The objective of this study is to calibrate Priestley-Taylor (PT) model for estimating open water evaporation from an arid region reservoir called Chahnimeh. Chahnimeh Reservoir which is situated in the Sistan area in the southeast of Iran is being affected by regional energy advection during May to October. Therefore, common models of open water evaporation estimation such as PT require calibration. PT method was calibrated for Chahnimeh Reservoir using a volume balance method. Results showed that PT coefficient, αPT, as a constant over the year varies between 2.47±0.09 and 1.20±0.03 for two different hydrologic conditions of dry and wet. It means that there is also an intra-annular... 

In the present work, graphene oxide (GO) and reduced graphene oxide (RGO) were incorporated at low-density polyethylene (LDPE)/ethylene vinyl acetate (EVA) copolymer blend using solution casting method. Monolayer GO with 1-nm thickness and good transparency was synthesized using the well-known Hummers's method. Fourier transform infrared and X-ray photoelectron spectroscopy data exhibited efficient reduction of GO with almost high C/O ratio of RGO. Scanning electron microscopy showed the well distribution of GO and RGO within LDPE/EVA polymer matrix. The integrating effects of GO and RGO on mechanical and gas permeability of prepared films were examined. Young's modulus of nanocomposites are... 

Virtual organization (VO) is aimed to provide inter-organizational collaborations. Constructing a VO necessitates provision of security and access control requirements which cannot be satisfied using the traditional access control models. This is basically due to special features of VOs; such as temporality, unknown users, and diverse resources. In this paper, after expressing our assumption on a framework for VOs; the concept of organizational trust and reputation is used to establish an access control model for VOs. Each member of an organization inherits its organizational reputation. Resource providers announce the behavior of their interacting users to their organization manager.... 

Infills are as important members in structural design as beams, columns and braces. They have significant effect on structural behavior. Because of lots of variables in infills like material non-linear behavior, the interaction between frames and infill, etc., the infills performance during an earthquake is complicated, so have led designers do not consider the effect of infills in designing the structure. However, the experimental studies revealed that the infills have the remarkable effect on structure behavior. As if these effects ignored, it might occur soft-story phenomena, torsion or short-column effects on the structures. One simple and appropriate method for considering the infills... 

In this research, microstructure evaluation, mechanical properties and thermal conductivity of the Mg-SiCw/Cu composite with laminar structure were investigated. For this purpose, SiC whiskers were added to magnesium alloy by using stir-casting, then the Mg-SiCw composite was bonded to copper layers by warm accumulative roll bonding (ARB). Based on the results of optical microscopy (OM) and scanning electron microscopy (SEM), SiC whiskers were well distributed in the magnesium matrix and they were aligned parallelly when the composites were plastically deformed at higher rolling passes. Furthermore, all layers remained continuous with localized necking sites. Also, no intermetallic compounds... 

Conventional polygraphy has several alternatives and one of them is P300-based guilty knowledge test. The purpose of this paper is to apply a new method called empirical mode decomposition (EMD) to extract features from electroencephalogram (EEG) signal. EMD is an appropriate tool to deal with the nonlinear and nonstationary nature of EEG. In the previous studies on the same data set, some morphological, frequency, and wavelet features were extracted only from Pz channel, and used for the detection of guilty and innocent subjects. In this paper, an EMD-based feature extraction was done on EEG recorded signal. Features were extracted from all three recorded channels (Pz, Cz, and Fz) for... 

Hybrid nanofluids provide better thermal network, mechanical resistance, good aspect ratio and thermal conductivity rather than usual/mono nanofluids. The hybrid nano-composition of multi-wall carbon nanotubes and nickel zinc ferrites possesses superior thermal properties and embellished heat transfer characteristics. The main concern, in this paper, is to examine the novel thermal aspects of water based pure nanofluid (MWCNTs) and hybrid nanofluid (MWCNTs-NiZnFe2O4). The prominent effects of viscous dissipation, motile gyrotactic microorganisms and activation energy have also been taken into account. The other aspect of the study is also to interpret the flow features of hybrid nanofluids...