Probabilistic Graphical models in Recommender systems

, M.Sc. Thesis Sharif University of Technology Seyed Aboutorabi, Hediyeh Sadat (Author) ; Moghadasi, Reza (Supervisor)

Abstract

In recommender systems, the available data structure is mostly in the form of a graph; Therefore, during the past years, graph based recommendation methods, especially Graph neural networks, have received a lot of attention. These networks obtain the representation of user nodes and items by aggregating multi-hop neighbors in different ways. Unfortunately, the existing methods are part of the Supervised learning scenario and due to the lack of data in recommender systems, they have faced serious challenges. These challenges reduce the ability to learn to representation nodes and the accuracy of recommendations. Recently, knowledge graph based recommendations have achieved excellent...

Preparation and characterization of nanostructured TiO2thin film codoped with nitrogen and vanadium on glass surface by sol–gel dip-coating method

, Article Research on Chemical Intermediates ; 2014 ; ISSN: 09226168 Khatibnezhad, H ; Sani, M. A. F ; Sharif University of Technology

2014

Abstract

To enhance hydrophilicity and photocatalytic activity, N-doped and N–V-codoped TiO2films were coated on glass substrates by the sol–gel dip-coating method. The substrates were previously coated with SiO2using the same method. The coated samples, after annealing at 450 °C for 30 min in air, were analyzed by an X-ray diffractometer, scanning electron microscope, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, and UV–visible spectroscope. The SiO2/N–V-codoped TiO2photocatalyst showed a narrower band gap (2.93 eV) compared to the SiO2/N-doped. Degradation tests, methyl orange under UV light and stearic acid under visible light, were performed in order to evaluate...

Preparation and characterization of nanostructured TiO2 thin film codoped with nitrogen and vanadium on glass surface by sol-gel dip-coating method

, Article Research on Chemical Intermediates ; Volume 41, Issue 10 , October , 2015 , Pages 7349-7361 ; 09226168 (ISSN) Khatibnezhad, H ; Sani, M. A. F ; Sharif University of Technology

Kluwer Academic Publishers 2015

Abstract

To enhance hydrophilicity and photocatalytic activity, N-doped and N-V-codoped TiO2 films were coated on glass substrates by the sol-gel dip-coating method. The substrates were previously coated with SiO2 using the same method. The coated samples, after annealing at 450 °C for 30 min in air, were analyzed by an X-ray diffractometer, scanning electron microscope, Fourier transform infrared spectroscope, X-ray photoelectron spectroscope, and UV-visible spectroscope. The SiO2/N-V-codoped TiO2 photocatalyst showed a narrower band gap (2.93 eV) compared to the SiO2/N-doped. Degradation tests, methyl orange under UV light and stearic acid...

Optimization of acid leaching of rutile containing slag using factorial based response surface modeling

, Article Indian Journal of Science and Technology ; Volume 9, Issue 4 , 2016 , Pages 1-8 ; 09746846 (ISSN) Abazarpoor, A ; Halali, M ; Khatibnezhad, H ; Sharif University of Technology

Indian Society for Education and Environment 2016

Abstract

In this study the leaching of a high rutile containing slag in sulphuric acid has been investigated to find optimum leaching conditions. Using "Fractional Factorial" technique it was deduced that leaching temperature and duration, acid concentration and particle size are the most prominent parameters in the leaching process. The optimization of the leaching process was investigated using the "Rotatable Central Composite Design" technique. The four prominent parameters were studied at 5 different test values each. 3D response surface was employed to illustrate interaction of the parameters. The optimum leaching conditions for the ilmenite concentrate are thus recognized as: T = 123.9°C, time...

An Investigation on Photocatalytic Behavior of N-doped and N-V-doped TiO2 Thin Film, Coated on Glass Surface by Sol-gel Dip Coating Method

, M.Sc. Thesis Sharif University of Technology Khatibnezhad, Hediyeh (Author) ; Faghihi Sani, Mohammad Ali (Supervisor)

Abstract

In this study, the photocatalytic activity and hydrophilicity of coat improved using Nitrogen and Vanadium elements as dopant in TiO2 coating. By using vanadium and nitrogen elements and silica prelayer, a titania coating was deposited on the soda-lime glass substrate by sol-gel dip coating method to produce self-cleaning surface. XRD and FTIR analyses were done on the powders after heat treating at in 450˚C for 30 min. XPS analysis was done for investigation of N replacement in titania structure. The band-gap energy of formed anatase was derived using UV-Vis analysis. The coating morphology and thickness were also investigated by SEM. Hydrophilicity of coatings was determined by measuring...