Sharif Digital Repository

In this paper we study envy free pricing problem in general graphs where there is not a seller in every graph's nodes. We assume unique establishment cost for initiating a store in each node and we wish to find an optimal set of nodes in which we would make the maximum profit by initiating stores in them. Our model is motivated from the observation that a same product has different prices in different locations and there is also an establishing cost for initiating any store. We consider both of these issues in our model: first where should we establish the stores, and second at what price should we sell our items in them to gain maximum possible profit. We prove that in a case of constant... 

A Solvent-free microwave-assisted green approach has been presented the synthesis of dispiropyrrolidineoxindole compounds with regio- and stereoselectivity and the excellent yields in short reaction times. A comparative study of the synthesis of dispiropyrrolidineoxindole derivatives by conventional heating and microwave condition has been described by the cycloaddition of azomethine ylides generated from sarcosine and isatin with the dipolarophile aurones. Molecular docking studies were carried out to explore the synthesized bispirooxindoles as inhibitors of CDK5. One of these compounds exhibited excellent binding affinity for cyclin dependent kinases (CDK5). Also, the structures were... 

In this research, Ag-Al2O3 nanostructures have been prepared via combustion synthesis and ammonium acetate and urea have been applied as fuels. The prepared Ag-Al2O3 nanostructures were characterized by DTA, XRD, SEM, TEM, and BET spectroscopy. The effect of different ratios of silver to alumina and fuel percentage on morphology and particle size of prepared products were investigated. The results showed that using ammonium acetate fuel led to the production of Ag-γ-Al2O3 nanocompounds, while using urea produced Ag-α-Al2O3. Also, the photocatalytic activity of Ag-Al2O3 nanostructures for Congo red degradation was evaluated by UV-Vis diffuse reflectance spectroscopy. The photocatalytic... 

This paper is an attempt to develop a design methodology for a special deployable structure for potential use in micro-satellites. The basic form of this structure is a hexagonal prismatic tensegrity structure, which, after being rigidified, is used as the supporting structure of a mesh-like antenna. Here, the objectives of presenting the design methodology are to prevent structural elements from failure, while maintaining the structural natural frequency and mesh tension above an intended value and in addition, to minimize the overall mass. Here, the suggested design strategy combines the need for a behavioral study (i.e. fast and wide range evaluation) at the beginning of the design, with... 

With thousands of new questions posted every day on popular Q&A websites, there is a need for automated and accurate software solutions to replace manual moderation. In this paper, we address the critical drawbacks of crowdsourcing moderation actions in Q&A communities and demonstrate the ability to automate moderation using the latest machine learning models. From a technical point, we propose a multi-view approach that generates three distinct feature groups that examine a question from three different perspectives: 1) question-related features extracted using a BERT-based regression model; 2) context-related features extracted using a named-entity-recognition model; and 3) general lexical... 

Single-layer MoS2-MoO3-x heterojunction nanosheets with visible-light-sensitive band gap energy and average lateral dimensions of ~70 nm were synthesized by using a two-step combined exfoliation method. The exfoliation was initiated from pristine MoS2, while some sulfur sites in expanded MoS2 sheets during exfoliating were substituted by ambient non-thermal oxygen, resulting in formation of α-MoO3-x crystalline domains. The morphological features, crystalline structure, phase formation, number of layers, and optical properties of the MoS2-MoO3-x nanosheets were determined by atomic force microscopy; X-ray diffraction; field emission electron microscopy; transmission electron microscopy; and...