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Trajectory design for cooperative combat missions
, Article 2008 IEEE Aerospace Conference, AC, Big Sky, MT, 1 March 2008 through 8 March 2008 ; 2008 ; 1095323X (ISSN) ; 1424414881 (ISBN); 9781424414888 (ISBN) ; Sharif University of Technology
2008
Abstract
In this paper, a hierarchical method for trajectory design for cooperative combat missions (CCM) is presented. In a military environment, in addition to physical constraints (aircraft dynamics and mountains) there are threats made by Radars or Artillery. So an important constraint, "Avoid Threats", is added to physical constraints. Major steps in trajectory design are: "Target Assignment", "Path Planning", "Path Smoothing and Trajectory Design". The most important points and a brief algorithm for each step is presented in this paper. Finally the method is applied to special case and the results presented. ©2008 IEEE
Planning And Scheduling Operating Rooms by Using Modified Block Scheduling Strategy with Considering the Surgical Team and post- Operative Units Constraints
, M.Sc. Thesis Sharif University of Technology ; Salmasi, Naser (Supervisor)
Abstract
provide about 67% of a hospital’s profit. Hospital managers are interested in decreasing the costs as well as increasing the customers’ satisfaction level. In this Thesis, four Mixed- Integer Programming models for planning and scheduling operating rooms are proposed. In the main, the problem is presented in two phases. In The first phase, model assigns the date and the room to each surgical and in second phase the model determines the sequencing of the assigned operation cases. The effects of using three different scheduling strategies (Block and Open and modified block) for assigning operating rooms to surgeons on the planning of surgical cases is studied. Then we proposed one phase model...
Using machine learning to predict mortality for covid-19 patients on day 0 in the ICU
, Article Frontiers in Digital Health ; Volume 3 , 2022 ; 2673253X (ISSN) ; Asgary, A ; Tavakoli, N ; Zali, A ; Setareh, S ; Esmaily, H ; Jamaldini, S. H ; Daaee, A ; Babajani, A ; Sendani Kashi, M. A ; Jamshidi, M ; Jamal Rahi, S ; Mansouri, N ; Sharif University of Technology
Frontiers Media S.A
2022
Abstract
Rationale: Given the expanding number of COVID-19 cases and the potential for new waves of infection, there is an urgent need for early prediction of the severity of the disease in intensive care unit (ICU) patients to optimize treatment strategies. Objectives: Early prediction of mortality using machine learning based on typical laboratory results and clinical data registered on the day of ICU admission. Methods: We retrospectively studied 797 patients diagnosed with COVID-19 in Iran and the United Kingdom (U.K.). To find parameters with the highest predictive values, Kolmogorov-Smirnov and Pearson chi-squared tests were used. Several machine learning algorithms, including Random Forest...
Temperature gradient and wind profile effects on heavy gas dispersion in build up area
, Article Journal of Applied Sciences Research ; Volume 6, Issue 12 , 2010 , Pages 6010-6020 ; 1816157X (ISSN) ; Shahraki, F ; Rashtchian, D ; Behzadmehr, A ; Sharif University of Technology
2010
Abstract
Dispersion of heavy gases is considered to be more hazardous than the passive ones. This is because it takes place more slowly. In this paper, based on the extensive experimental work of Hanna and Chang, the CFD model (Ansys-CFX) was tested compared with Kit Fox experiments. In order to accomplish this validation, the multiphase approach was employed as a new method in this area. In addition, the temperature gradient effects were investigated. The survey of wind speed was done taking factors such as time, height and direction into the consideration. To reduce the number of elements in computational domain, a combination of 2D and 3D geometries were utilized. Results showed that the wind...
Temperature gradient and wind profile effects on heavy gas dispersion in build up area
, Article Australian Journal of Basic and Applied Sciences ; Volume 4, Issue 12 , 2010 , Pages 6010-6020 ; 19918178 (ISSN) ; Shahraki, F ; Rashtchian, D ; Behzadmehr, A ; Sharif University of Technology
2010
Abstract
Dispersion of heavy gases is considered to be more hazardous than the passive ones. This is because it takes place more slowly. In this paper, based on the extensive experimental work of Hanna and Chang, the CFD model (Ansys-CFX) was tested compared with Kit Fox experiments. In order to accomplish this validation, the multiphase approach was employed as a new method in this area. In addition, the temperature gradient effects were investigated. The survey of wind speed was done taking factors such as time, height and direction into the consideration. To reduce the number of elements in computational domain, a combination of 2D and 3D geometries were utilized. Results showed that the wind...
Organic halides and nanocone plastic structures enhance the energy conversion efficiency and self-cleaning ability of colloidal quantum dot photovoltaic devices
, Article Journal of Physical Chemistry C ; Volume 121, Issue 18 , 2017 , Pages 9757-9765 ; 19327447 (ISSN) ; Simchi, A ; Tavakoli, R ; Fan, Z ; Sharif University of Technology
American Chemical Society
2017
Abstract
This paper presents solid-state ligand exchange of spin-coated colloidal lead sulfide quantum dot (PbS QD) films by methylammonium iodide (MAI) and integration of them in depleted heterojunction solar (DHS) devices having an antireflecting (AR) nanocone plastic structure. Time-resolved photoluminescence measurements determine a shorter lifetime of the charge carries on a semiconductor (TiO2) electron transfer layer for the MAI-passivated QD films as compared with those with long-chain aliphatic or short thiol ligands. Consequently, the DHS device yields improved power conversion efficiency (>125%) relative to oleic-acid-passivated PbS QD films. Using anodized aluminum oxide templates, an...
Audio watermarking based on quantization index modulation in the frequency domain
, Article 2007 IEEE International Conference on Signal Processing and Communications, ICSPC 2007, Dubai, 14 November 2007 through 27 November 2007 ; 2007 , Pages 1127-1130 ; 9781424412365 (ISBN) ; Akhaee, M. A ; Ahadi, S. M ; Moradi, M ; Kashi, A ; Sharif University of Technology
2007
Abstract
In this paper, our main purpose is to embed data in the frequency domain of audio signals. Data was embedded by means of Quantization Index Modulation (QIM) in the frequency domain. With this aim, the spectrum of the audio signal was divided into two parts. The first part consisted of the first 19 Barks and the second included the remaining 6 Barks. Each of these parts had a different quantization step size. In order to have large quantization step sizes which yield more robustness, Human Auditory System (HAS) has been used. Decoder detects the watermark signal, without using the original audio signal. Simulation results have shown that this watermarking scheme has better robustness against...
Room temperature selective sensing of aligned Ni nanowires using impedance spectroscopy
, Article Materials Research Express ; Volume 7, Issue 2 , 24 February , 2020 ; Fardindoost, S ; Iraji Zad, A ; Almasi Kashi, M ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
Room temperature gas sensing behavior of arrayed one-dimensional (1D) nickel nanowires (Ni NWs) are investigated using impedance spectroscopy. Ni nanowires synthesized via electrochemical deposition method based on anodic aluminum oxide (AAO) templates. Their structural characterization verified by scanning electron microscopy (SEM), x-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR) analysis. Impedance spectroscopy as an essential technique utilized to understand the mechanism of gas interaction with the wires through the changes in their electronic behavior. Bode and Nyquist plots with the real and imaginary impedances are plotted versus frequency range of 500 Hz...
An nnovative test bed for verification of attitude control system
, Article IEEE Aerospace and Electronic Systems Magazine ; Volume 32, Issue 6 , 2017 , Pages 16-22 ; 08858985 (ISSN) ; Faghihinia, A ; Kalhor, A ; Sharif University of Technology
2017
Abstract
A 3 DOF platform was constructed in the Georgia Institute of Technology to perform new control strategies in an experimental framework. Also in this simulator, there isn't any sensor used by a real satellite for attitude determination. The setup was structured on data transmitting and synchronization of distributed elements for ADCS tests. In such a plan, not only can different elements of the test bed be used individually, but also they can support an integrated hardware in the loop test. Accordingly, reusing the hardware sources causes a cost reduction of development. Furthermore the geometric interferences of different parts are minimized in this plan. So, the test bed can be developed...
Symptom prediction and mortality risk calculation for COVID-19 using machine learning
, Article Frontiers in Artificial Intelligence ; Volume 4 , June , 2021 ; 26248212 (ISSN) ; Asgary, A ; Tavakoli, N ; Zali, A ; Dastan, F ; Daaee, A ; Badakhshan, M ; Esmaily, H ; Jamaldini, S. H ; Safari, S ; Bastanhagh, E ; Maher, A ; Babajani, A ; Mehrazi, M ; Sendani Kashi, M. A ; Jamshidi, M ; Sendani, M. H ; Rahi, J ; Mansouri, N ; Sharif University of Technology
Frontiers Media S. A
2021
Abstract
Background: Early prediction of symptoms and mortality risks for COVID-19 patients would improve healthcare outcomes, allow for the appropriate distribution of healthcare resources, reduce healthcare costs, aid in vaccine prioritization and self-isolation strategies, and thus reduce the prevalence of the disease. Such publicly accessible prediction models are lacking, however. Methods: Based on a comprehensive evaluation of existing machine learning (ML) methods, we created two models based solely on the age, gender, and medical histories of 23,749 hospital-confirmed COVID-19 patients from February to September 2020: a symptom prediction model (SPM) and a mortality prediction model (MPM)....
Supercritical Carbon Dioxide Extraction of Catechins from Green Tea Leaves
, M.Sc. Thesis Sharif University of Technology ; Goodarznia, Iraj (Supervisor)
Abstract
Green tea has been receiving significant attention in recent years due to its high content of catechins; Epicatechin (EC), epicatechin gallate (ECG), epigallocatechin (EGC) and especially epigallocatechin gallate (EGCG). As powerful antioxidants, these compounds are believed to have several health benefits. In this study, we used supercritical CO2 with ethanol as co-solvent to extract catechin derivatives from green tea and we investigated the effects of experiment parameters on the extraction. Experiments, designed according to Taguchi algorithm, were conducted with green tea particles of four average diameters of 1500, 855, 605 and 427.5 µm, in an interval of 35- 55 ̊C for temperature and...
Efficient removal of cationic dyes using a new magnetic nanocomposite based on starch-g-poly(vinylalcohol) and functionalized with sulfate groups
, Article RSC Advances ; Volume 6, Issue 44 , 2016 , Pages 38042-38051 ; 20462069 (ISSN) ; Abedin Moghanaki, A ; Tavakoli, A ; Sharif University of Technology
Royal Society of Chemistry
2016
Abstract
A magnetic nanoparticle@starch-g-poly(vinyl sulfate) nanocomposite (MNP@St-g-PVS) as a new magnetic nano-adsorbent has been prepared based on graft copolymerization of vinyl acetate onto starch in the presence of magnetic nanoparticles, where the acetate groups were converted to hydroxyl groups followed by the sulfation of the hydroxyl groups using chlorosulfonic acid. Characterization of this magnetic nanocomposite was carried out by FTIR, TGA, XRD, VSM, SEM, TEM and elemental analysis. The resulting nanocomposite was used as an adsorbent for the removal of typical cationic dyes, methylene blue (MB) and malachite green (MG), from aqueous solutions. All experimental parameters that can...
Design of Wired/Wireless Hybrid 3D NoC for Radio Components and 3D Digital Structure Compliance
, M.Sc. Thesis Sharif University of Technology ; Hessabi, Shaahin (Supervisor)
Abstract
According to recent advancements in digital circuit technology and new constraints for digital systems, scholars have researched to find a replacement for traditional copper links that is used to connect the embedded processing elements in a chip. Optic NoCs and wireless NoCs are two promising solutions to overcome challenges in traditional NoCs.
In this thesis, an innovative 3D NoC architecture is proposed which consists of four 2D mesh-based networks and they are connected via four wireless sub-networks as backbones. It is estimated that, the proposed architecture shrinks the power consumption at least 35 percent relatively due to the gate-level simulations. Thus, a better scaling and...
In this thesis, an innovative 3D NoC architecture is proposed which consists of four 2D mesh-based networks and they are connected via four wireless sub-networks as backbones. It is estimated that, the proposed architecture shrinks the power consumption at least 35 percent relatively due to the gate-level simulations. Thus, a better scaling and...
Improving quality of a post's set of answers in stack overflow
, Article 46th Euromicro Conference on Software Engineering and Advanced Applications, SEAA 2020, 26 August 2020 through 28 August 2020 ; 2020 , Pages 504-512 ; Izadi, M ; Heydarnoori, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
Community Question Answering platforms such as Stack Overflow help a wide range of users solve their challenges on-line. As the popularity of these communities has grown over the years, both the number of members and posts have escalated. Also, due to the diverse backgrounds, skills, expertise, and viewpoints of users, each question may obtain more than one answer. Therefore, the focus has changed toward producing posts that have a set of answers more valuable for the community as a whole, not just one accepted-answer aimed at satisfying only the question-asker. Same as every universal community, a large number of low-quality posts on Stack Overflow require improvement. We call these posts...
Study of the compaction behavior of composite powders under monotonic and cyclic loading
, Article Composites Science and Technology ; Volume 65, Issue 14 , 2005 , Pages 2094-2104 ; 02663538 (ISSN) ; Simchi, A ; Seyed Reihani, S. M ; Sharif University of Technology
2005
Abstract
The consolidation behavior of composite powders during pressure cycling at room temperature in uniaxial compaction experiments was studied and compared with monotonic compaction. Aluminum and various amounts of SiC powders (up to 50 vol%) were used to investigate the effect of hard reinforcement particle on the densification of soft aluminum matrix. The cyclic compaction was carried out at various pressure amplitudes, ranges from 90 to 360 MPa, at the frequency of 1 Hz. The pressure cycling was continued up to 5000 cycle, in which, the rate of consolidation was found to be fairly low. The consolidation of the composite powders under different loading modes was analyzed through...
Supercritical synthesis and in situ deposition of PbS nanocrystals with oleic acid passivation for quantum dot solar cells
, Article Materials Chemistry and Physics ; Volume 156 , 2015 , Pages 163-169 ; 02540584 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Colloidal quantum dot solar cells have recently attracted significant attention due to their low-processing cost and surging photovoltaic performance. In this paper, a novel, reproducible, and simple solution-based process based on supercritical fluid toluene is presented for in situ growth and deposition PbS nanocrystals with oleic-acid passivation. A lead precursor containing sulfur was mixed with oleic acid in toluene and processed in a supercritical fluid condition at different temperatures of 140, 270 and 330 °C for 20 min. The quantum dots were deposited on a fluorine-doped tin oxide glass substrate inside the supercritical reactor. Transmission electron microscopy, X-ray diffraction,...
SHTV, as a technique for core calculation using spatial homogenization and temperature variation
, Article Annals of Nuclear Energy ; Volume 37, Issue 9 , 2010 , Pages 1129-1138 ; 03064549 (ISSN) ; Zahedinejad, E ; Kashi, S ; Davilu, H ; Sharif University of Technology
2010
Abstract
The accuracy of static neutronic parameters in the nuclear reactors depends upon the determination of group constants of the diffusion equation in the desired geometry. Although several methods have been proposed for calculating these parameters, there is still the need for more reliable methods. In this paper a powerful and innovative method based on Spatial Homogenization and Temperature Variation (SHTV) of physical properties of a WWER-1000 nuclear reactor core for calculating the relative power distribution of Fuel Assemblies (FA) and the hot fuel rod, is presented. The method is based on replacing the heterogeneous lattices of materials with different properties by an equivalent...
Surface engineering of TiO2 ETL for highly efficient and hysteresis-less planar perovskite solar cell (21.4%) with enhanced open-circuit voltage and stability
, Article Advanced Energy Materials ; Volume 8, Issue 23 , 2018 ; 16146832 (ISSN) ; Yadav, P ; Tavakoli, R ; Kong, J ; Sharif University of Technology
Wiley-VCH Verlag
2018
Abstract
Interfacial studies and band alignment engineering on the electron transport layer (ETL) play a key role for fabrication of high-performance perovskite solar cells (PSCs). Here, an amorphous layer of SnO2 (a-SnO2) between the TiO2 ETL and the perovskite absorber is inserted and the charge transport properties of the device are studied. The double-layer structure of TiO2 compact layer (c-TiO2) and a-SnO2 ETL leads to modification of interface energetics, resulting in improved charge collection and decreased carrier recombination in PSCs. The optimized device based on a-SnO2/c-TiO2 ETL shows a maximum power conversion efficiency (PCE) of 21.4% as compared to 19.33% for c-TiO2 based device....
Efficient, hysteresis-free, and flexible inverted perovskite solar cells using all-vacuum processing.Efficient, hysteresis-free, and flexible inverted perovskite solar cells using all-vacuum processing
, Article Solar RRL ; 2020 ; Yadav, P ; Prochowicz, D ; Tavakoli, R ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
The fabrication of efficient perovskite solar cells (PSCs) using all-vacuum processing is still challenging due to the limitations in the vacuum deposition of the hole transporting layer (HTL). Herein, inverted PSCs using copper (II) phthalocyanine (CuPC) as an ideal alternative HTL for vacuum processing are fabricated. After proper optimization, a PSC with a power conversion efficiency (PCE) of 20.3% is achieved, which is much better than the PCEs (16.8%) of devices with solution-based CuPC. As it takes a long time to dissolve CuPC in the solution-based device, the evaporation approach has better advantage in terms of fast processing. In addition, the device with the evaporated CuPC HTL...
Efficient perovskite solar cells based on Cdse/Zns quantum dots electron transporting layer with superior UV stability
, Article Physica Status Solidi - Rapid Research Letters ; Volume 14, Issue 6 , 2020 ; Prochowicz, D ; Yadav, P ; Tavakoli, R ; Sharif University of Technology
Wiley-VCH Verlag
2020
Abstract
Stability is the main challenge in the field of perovskite solar cells (PSCs). Finding new strategies is required to protect the PSCs from deteriorating agents such as humidity, heating, and illumination. Herein, a new electron transporting layer (ETL), i.e., CdSe/ZnS quantum dots (QDs), is proposed for the fabrication of efficient and stable PSCs. CdSe/ZnS QDs layer not only works as an ETL but also has downshifting property, which can improve both efficiency and stability of the PSCs. Using CdSe/ZnS QDs ETL with green emission, a PSC with maximum power conversion efficiency (PCE) of 18% is achieved. More importantly, the device shows great UV stability, much better than the device with...