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regulators
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A sustainable supply chain under VMI-CS agreement with withdrawal policies for imperfect items
, Article Journal of Cleaner Production ; Volume 376 , 2022 ; 09596526 (ISSN) ; Fallahi, A ; Mokhtari, H ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Supply Chain (SC) coordination, quality requirements, and environmental issues are the main areas of interest within the field of inventory management. Few studies have integrated these concepts into an inventory problem despite its overwhelming necessity. In this direction, this paper deals with a vendor-buyer SC under the Vendor-Managed Inventory with Consignment Stock (VMI-CS) agreement. According to the agreement, the vendor bears the buyer's financial holding cost in return for the storage of products in the buyer's warehouse. Further, each shipment involves a random fraction of repairable items, which need to be withdrawn from the inventory system. Unlike the existing literature, when...
A constrained multi-item EOQ inventory model for reusable items: Reinforcement learning-based differential evolution and particle swarm optimization
, Article Expert Systems with Applications ; Volume 207 , 2022 ; 09574174 (ISSN) ; Amani Bani, E ; Akhavan Niaki, S. T ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
The growing environmental concerns, governmental regulations, and significant cost savings are the primary motivations for companies to consider the reuse and recovery of products in their inventory system. The previous research ignored several realistic features of reusable items inventory systems, such as the presence of multiple products and operational constraints. For the first time, this paper presents a new multiproduct economic order quantity inventory model for an inventory system of reusable products. The goal of the model is to determine the optimal replenishment quantity and reuse quantity of each item so that the system's total cost is minimized. Several operational constraints...
Robust output regulation: optimization-based synthesis and event-triggered implementation
, Article IEEE Transactions on Automatic Control ; Volume 67, Issue 7 , 2022 , Pages 3529-3536 ; 00189286 (ISSN) ; Proskurnikov, A. V ; Tavazoei, M. S ; Esfahani, P. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
In this article, we investigate the problem of practical output regulation, i.e., to design a controller that brings the system output in the vicinity of a desired target value while keeping the other variables bounded. We consider uncertain systems that are possibly nonlinear and the uncertainty of their linear parts is modeled element wise through a parametric family of matrix boxes. An optimization-based design procedure is proposed that delivers a continuous-time control and estimates the maximal regulation error. We also analyze an event-triggered emulation of this controller, which can be implemented on a digital platform, along with an explicit estimate of the regulation error. ©...
Downregulation of oxytocin-related genes in periodontitis
, Article Frontiers in Molecular Neuroscience ; Volume 15 , 2022 ; 16625099 (ISSN) ; Gholami, L ; Nazer, N ; Hussen, B. M ; Sayad, A ; Hajiesmaeili, M ; Sharif University of Technology
Frontiers Media S.A
2022
Abstract
Periodontitis is a common oral disorder leading to tooth loss in both developed and developing regions of the world. This multifactorial condition is related to the abnormal activity of several molecular pathways, among them are oxytocin-related pathways. In this study, we enrolled 26 patients and 28 controls and assessed the expression of four oxytocin-related genes, namely, FOS, ITPR, RCAN1, and RGS2, in circulation and affected tissues of enrolled individuals using real-time PCR. Expression of FOS was downregulated in total periodontitis tissues compared with total control tissues [ratio of mean expression (RME) = 0.23, P-value = 0.03]. Expression of FOS was also lower in total blood...
Model-free LQR design by Q-function learning
, Article Automatica ; Volume 137 , 2022 ; 00051098 (ISSN) ; Babazadeh, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Reinforcement learning methods such as Q-learning have shown promising results in the model-free design of linear quadratic regulator (LQR) controllers for linear time-invariant (LTI) systems. However, challenges such as sample-efficiency, sensitivity to hyper-parameters, and compatibility with classical control paradigms limit the integration of such algorithms in critical control applications. This paper aims to take some steps towards bridging the well-known classical control requirements and learning algorithms by using optimization frameworks and properties of conic constraints. Accordingly, a new off-policy model-free approach is proposed for learning the Q-function and designing the...
Pan-cancer analysis of microRNA expression profiles highlights microRNAs enriched in normal body cells as effective suppressors of multiple tumor types: A study based on TCGA database
, Article PLoS ONE ; Volume 17, Issue 4 April , 2022 ; 19326203 (ISSN) ; Kamal, A ; Es, H. A ; Farhadi, F ; Ebrahimi, M ; Chitsaz, H ; Sharifi Zarchi, A ; Baharvand, H ; Sharif University of Technology
Public Library of Science
2022
Abstract
Background MicroRNAs (miRNAs) are frequently deregulated in various types of cancer. While antisense oligonucleotides are used to block oncomiRs, delivery of tumour-suppressive miRNAs holds great potential as a potent anti-cancer strategy. Here, we aim to determine, and functionally analyse, miRNAs that are lowly expressed in various types of tumour but abundantly expressed in multiple normal tissues. Methods The miRNA sequencing data of 14 cancer types were downloaded from the TCGA dataset. Significant differences in miRNA expression between tumor and normal samples were calculated using limma package (R programming). An adjusted p value < 0.05 was used to compare normal versus tumor miRNA...
Effect of Zn/Sn ratio on perovskite solar cell performance applying off-stoichiometric Cu2ZnSnS4/Carbon hole-collecting electrodes
, Article ACS Applied Materials and Interfaces ; Volume 14, Issue 15 , 2022 , Pages 17296-17311 ; 19448244 (ISSN) ; Forouzandeh, M ; Taghavinia, N ; Mahdavi, S. M ; Sharif University of Technology
American Chemical Society
2022
Abstract
Low-cost inorganic hole-transporting materials (HTMs) accompanied by a printable carbon electrode is an efficient approach to address the limitation of material cost of perovskite solar cells (PSCs) and get this technology closer to commercialization. The present work is focused on optimizing the Zn/Sn ratio of Cu2ZnSnS4/carbon hole collectors in n-i-p structured PSCs, where CuInS2/carbon is applied as the reference hole collector. This composition regulation is a solution to address the challenge of composition-related defects of the Cu2ZnSnS4 (CZTS) material. The Zn/Sn ratio was tuned by the initial proportion of the zinc precursor during the nanoparticle (NP) synthesis using a heating-up...
MaxHiC: A robust background correction model to identify biologically relevant chromatin interactions in Hi-C and capture Hi-C experiments
, Article PLoS Computational Biology ; Volume 18, Issue 6 , 2022 ; 1553734X (ISSN) ; Modegh, R. G ; Rabiee, H. R ; Sarbandi, E. R ; Rezaie, N ; Tam, K. T ; Forrest, A. R. R ; Sharif University of Technology
Public Library of Science
2022
Abstract
Hi-C is a genome-wide chromosome conformation capture technology that detects interactions between pairs of genomic regions and exploits higher order chromatin structures. Conceptually Hi-C data counts interaction frequencies between every position in the genome and every other position. Biologically functional interactions are expected to occur more frequently than transient background and artefactual interactions. To identify biologically relevant interactions, several background models that take biases such as distance, GC content and mappability into account have been proposed. Here we introduce MaxHiC, a background correction tool that deals with these complex biases and robustly...
Multi model robust control design for a floating offshore variable speed wind turbine with tension leg platform
, Article Ocean Engineering ; Volume 266 , 2022 ; 00298018 (ISSN) ; Sadati, N ; Member, IEEE ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
This paper presents a multi-model robust control (MMRC) design for an offshore variable speed wind turbine with tension leg platform. The proposed control scheme covers the model uncertainty in the above rated wind speed, and it provides a reliable control for power regulation while minimizing the mechanical loads on the wind turbine structure. For this purpose, the above rated wind speed region is divided into several wind speed groups, and a set of linearized models are obtained from the Fatigue, Aerodynamics, Structures, and Turbulence (FAST) simulator for various mean wind speeds of each group. Using Weibull wind speed distribution, a nominal model with additive uncertainty is generated...
Hybrid modeling of quasi-resonant converters: A piecewise affine approach
, Article 13th Power Electronics, Drive Systems, and Technologies Conference, PEDSTC 2022, 1 February 2022 through 3 February 2022 ; 2022 , Pages 448-454 ; 9781665420433 (ISBN) ; Tahami, F ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
DC-DC quasi-resonant converters (QRC) have the advantage of reducing switching losses and electromagnetic interference (EMI) which are the main disadvantages of high frequency power converters. The control and stabilization of these converters have always been a challenge. Traditionally, the dynamical model of the QRC is obtained using state space averaging followed by linearization about an operating point. The major flaw of this method is that state variables have large variations; thus, the linearized averaged model is not valid. Therefore, it is necessary to obtain a more precise model for the aim of stability analysis and controller design. Due to semiconductors switching, QRCs are...
A mixed methods approach to exploring grammar learning strategies in self-regulation task phases: Evidence from grounded theory and regression analysis
, Article Language Teaching Research ; 2022 ; 13621688 (ISSN) ; Ranjbar, M ; Sharif University of Technology
SAGE Publications Ltd
2022
Abstract
While research into various dimensions of language learning strategies has been thriving over the recent years, grammar learning strategies (GLS) have largely remained under-explored. The present mixed methods research aimed to explore GLS in the three stages of classroom grammar tasks, while striving to determine the sequence of GLS and their contribution to grammar proficiency. In the qualitative phase, 13 participants partook in stimulated recall and semi-structured interviews after completing consciousness-raising (CR) tasks. Then, the grounded theory (GT) methodology was applied to conceptualize a theoretical model. For the quantitative phase, a modified version of Pawlak’s Grammar...
Design and optimization of a large-scale permanent magnet synchronous generator
, Article Scientia Iranica ; Volume 29, Issue 1 D , 2022 , Pages 217-229 ; 10263098 (ISSN) ; Rezazadeh, G ; Alipour Sarabi, R ; Tahami, F ; Sharif University of Technology
Sharif University of Technology
2022
Abstract
Direct-drive permanent magnet synchronous generators enjoy numerous advantages including improved reliability, low maintenance, long life, and developed performance characteristics. In recent years, many researchers have worked on these generators to enhance their performance, especially for the wind turbine application. The focus of this paper is on the development of a step-by-step method for the design of a permanent magnet synchronous generator. Then, the winding function method is used to model the generator and calculate its output characteristics analytically. The analytical results of the designed generator are validated using Finite Element Analysis (FEA) and it is demonstrated that...
Optimal equilibrium selection of price-maker agents in performance-based regulation market
, Article Journal of Modern Power Systems and Clean Energy ; Volume 10, Issue 1 , 2022 , Pages 204-212 ; 21965625 (ISSN) ; Sheikhi, A ; Ranjbar, A. M ; Sun, W ; Sharif University of Technology
State Grid Electric Power Research Institute Nanjing Branch
2022
Abstract
This paper analyzes the oligopolistic equilibria of multiple price-maker agents in performance-based regulation (PBR) markets. In these markets, there are price-maker agents representing some frequency regulation (FR) providers and a number of independent price-taker FR providers. A model of equilibrium problem with equilibrium constraints (EPECs) is employed in this paper to study the equilibria of a PBR market in the presence of price-maker agents and price-taker FR providers. Due to the incorporation of the FR providers' dynamics, the proposed model is reformulated as a mixed-integer linear programming (MILP) problem over innovative mathematical techniques. An optimal equilibrium point is...
The impact of employing a magnetic field as well as Fe3O4 nanoparticles on the performance of phase change materials
, Article Engineering Applications of Computational Fluid Mechanics ; Volume 16, Issue 1 , 2022 , Pages 196-214 ; 19942060 (ISSN) ; Moghaddas, A ; Kazemi, A ; Ahmadi, M ; Feshkache, H. N ; Ahmadi, M. H ; Sharifpur, M ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
In this study a 2D cubic chamber model filled with paraffin is analyzed with and without the inclusion of magnetic Fe3O4 nanoparticles at concentrations of 0.5, 1, 1.5 and 2 wt%, and an external magnetic field of intensities 0.005, 0.01, 0.015 and 0.02 T. It is ascertained that adding magnetic nanoparticles leads the horizontal temperature gradient to be reduced owing to increments in thermal conductivity. Additionally, this feature is found to be accelerated by applying an external magnetic field, which shapes highly conductive cluster formations of nanoparticles. However, since the increase in nanoparticle concentration and magnetic intensity increases the composite viscosity, there is an...
Delay-Independent regulation of blood glucose for type-1 diabetes mellitus patients via an observer-based predictor feedback approach by considering quantization constraints
, Article European Journal of Control ; Volume 63 , 2022 , Pages 240-252 ; 09473580 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Diabetes, as a widespread chronic disease, is caused by the increase of blood glucose concentration (BGC) due to pancreatic insulin production failure and/or insulin resistance in the body. The artificial pancreas (AP) known as a closed-loop insulin delivery control system consists of a glucose sensor for BGC measurement, a control algorithm for calculation of exogenous insulin delivery rate (IDR), and an insulin infusion pump. The AP provides a closed-loop glucose-insulin regulatory system for type-1 diabetes mellitus (T1DM) patients in order to effectively reduce the high BGC level. In this paper, we aim to design a controller in order to regulate the BGC of T1DM patients at its basal...
Glycan-mediated functional assembly of IL-1RI: structural insights into completion of the current description for immune response
, Article Journal of Biomolecular Structure and Dynamics ; Volume 40, Issue 6 , 2022 , Pages 2575-2585 ; 07391102 (ISSN) ; Ejtehadi, M. R ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Interleukin 1 Receptor type I (IL-1RI) is a multi-domain transmembrane receptor that triggers the inflammatory response. Understanding its detailed mechanism of action is crucial for treating immune disorders. IL-1RI is activated upon formation of its functional assembly that occurs by binding of the IL-1 cytokine and the accessory protein (Il-1RAcP) to it. X-ray crystallography, small-Angle X-ray Scattering and molecular dynamics simulation studies showed that IL-1RI adopts two types of ‘compact’ and ‘extended’ conformational states in its dynamical pattern. Furthermore, glycosylation has shown to play a critical role in its activation process. Here, classical and accelerated atomistic...
Wind-tolerant optimal closed loop controller design for a domestic atmospheric research airship
, Article Mechanics Based Design of Structures and Machines ; Volume 50, Issue 6 , 2022 , Pages 2046-2066 ; 15397734 (ISSN) ; Pourtakdoust, S. H ; Pazooki, F ; Sharif University of Technology
Taylor and Francis Ltd
2022
Abstract
Airships are inherently sensitive to random atmospheric disturbances that could potentially make their data gathering and observation missions a formidable task. In this context robust closed loop feedback controllers are important. The present study is therefore focused on optimal feedback controller design of an indigenous domestically designed airship (DA) for added robustness against atmospheric disturbances. While the general airship six degrees of freedom (6DoF) governing equations of motion are mathematically nonlinear, one often needs to resort to local linearization methods to benefit from proven linear closed loop controller (CLC) design approaches. In this sense an optimal linear...
Co-delivery of letrozole and cyclophosphamide via folic acid-decorated nanoniosomes for breast cancer therapy: Synergic effect, augmentation of cytotoxicity, and apoptosis gene expression
, Article Pharmaceuticals ; Volume 15, Issue 1 , 2022 ; 14248247 (ISSN) ; Hosseini, E ; Karimifard, S ; Khayam, N ; Meybodi, S. M ; Amiri, S ; Bourbour, M ; Far, B. F ; Akbarzadeh, I ; Bhia, M ; Hoskins, C ; Chaiyasut, C ; Sharif University of Technology
MDPI
2022
Abstract
Breast cancer is one of the most prevalent causes of cancer mortality in women. In order to increase patient prognosis and survival rates, new technologies are urgently required to deliver therapeutics in a more effective and efficient manner. Niosome nanoparticles have been recently employed as therapeutic platforms capable of loading and carrying drugs within their core for both mono and combination therapy. Here, niosome-based nanoscale carriers were investigated as a targeted delivery system for breast cancer therapy. The platform developed consists of niosomes loaded with letrozole and cyclophosphamide (NLC) and surface-functionalized with a folic-acidtargeting moiety (NLCPFA). Drug...
Delivery of melittin-loaded niosomes for breast cancer treatment: an in vitro and in vivo evaluation of anti-cancer effect
, Article Cancer Nanotechnology ; Volume 12, Issue 1 , 2021 ; 18686958 (ISSN) ; Akbarzadeh, I ; Marzbankia, E ; Farid, M ; khaledi, L ; Reihani, A. H ; Javidfar, M ; Mortazavi, P ; Sharif University of Technology
BioMed Central Ltd
2021
Abstract
Background: Melittin, a peptide component of honey bee venom, is an appealing candidate for cancer therapy. In the current study, melittin, melittin-loaded niosome, and empty niosome had been optimized and the anticancer effect assessed in vitro on 4T1 and SKBR3 breast cell lines and in vivo on BALB/C inbred mice. "Thin-layer hydration method" was used for preparing the niosomes; different niosomal formulations of melittin were prepared and characterized in terms of morphology, size, polydispersity index, encapsulation efficiency, release kinetics, and stability. A niosome was formulated and loaded with melittin as a promising drug carrier system for chemotherapy of the breast cancer cells....
Optimal detailed design and performance assessment of natural gas pressure reduction stations system equipped with variable inlet guide vane radial turbo-expander for energy recovery
, Article Journal of Natural Gas Science and Engineering ; Volume 96 , 2021 ; 18755100 (ISSN) ; Rezaei, F ; Saboohi, Y ; Sharif University of Technology
Elsevier B.V
2021
Abstract
The turbo-expander system is utilized instead of the pressure regulator to avoid exergy destruction occurring in gas pressure reduction systems. However, due to the variation of natural gas input conditions such as mass flow rate, the sustainable performance of this technology is challenging. In this study, at first, the optimal system design of gas pressure reducing station equipped with radial expansion turbine is performed. It is based on economic and exergy analyses as well as considering geometric, fluid, thermodynamic constraints of components and the systematic constraints. To do so, detailed design models of main components including mean-line design model of radial turbine,...