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    Network and application-aware cloud service selection in peer-assisted environments

    , Article IEEE Transactions on Cloud Computing ; Volume 9, Issue 1 , 2021 , Pages 258-271 ; 21687161 (ISSN) Askarnejad, S ; Malekimajd, M ; Movaghar, A ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    There are a vast number of cloud service providers, which offer virtual machines (VMs) with different configurations. From the companies perspective, an appropriate selection of VMs is an important issue, as the proper service selection leads to improved productivity, higher efficiency, and lower cost. An effective service selection cannot be done without a systematic approach due to the modularity of requests, the conflicts between requirements, and the impact of network parameters. In this paper, we introduce an innovative framework, called PCA, to solve service selection problem in the hybrid environment of peer-assisted, public, and private clouds. PCA detects the conflicts between the... 

    Atomistic insight into the behavior of ions at an oil-bearing hydrated calcite surface: implication to ion-engineered waterflooding

    , Article Energy and Fuels ; Volume 35, Issue 16 , 2021 , Pages 13039-13054 ; 08870624 (ISSN) Badizad, M. H ; Koleini, M. M ; Greenwell, H. C ; Ayatollahi, S ; Ghazanfari, M. H ; Sharif University of Technology
    American Chemical Society  2021
    This research provides an atomistic picture of the role of ions in modulating the microstructural features of an oil-contaminated calcite surface. This is of crucial importance for the rational design of ion-engineered waterflooding, a promising technique for enhancing oil recovery from carbonate reservoirs. Inspired by a conventional lab-scale procedure, an integrated series of molecular dynamics (MD) simulations were carried out to resolve the relative contribution of the major ionic constituent of natural brines (i.e., Na+, Cl-, Mg2+, Ca2+, and SO42-) when soaking an oil-bearing calcite surface in different electrolyte solutions of same salinity, namely, CaCl2, MgCl2, Na2SO4, MgSO4, and... 

    Loss of lock-in in VIV due to spanwise variations of diameters

    , Article Ocean Engineering ; Volume 220 , 2021 ; 00298018 (ISSN) Bahramiasl, S ; De Langre, E ; Sharif University of Technology
    Elsevier Ltd  2021
    Elongated cylindrical structures with non-uniform diameters, under cross-flow, are often encountered in marine engineering and energy harvesting devices. In this work, the vortex-induced vibrations of elastically supported circular tapered and wavy cylinders with different cross sections areas are studied numerically using a wake oscillator model. The effect of the tapering ratio on the amplitude of oscillation is particularly analyzed. For tapered cylinders it is found that the amplitude of oscillation under flow decreases strongly when a critical tapering is reached. This is consistent with experimental data. A similar effect is found in wavy cylinders. A third system, consisting of a... 

    Biocompatible conductive alginate/polyaniline-graphene neural conduits fabricated using a facile solution extrusion technique

    , Article International Journal of Polymeric Materials and Polymeric Biomaterials ; Volume 70, Issue 7 , 2021 , Pages 486-495 ; 00914037 (ISSN) Bayat, A ; Ramezani Saadat Abadi. A ; Sharif University of Technology
    Bellwether Publishing, Ltd  2021
    In this study, conductive sodium alginate/polyaniline/graphene (PAG) NGCs were fabricated utilizing a straightforward solution extrusion method. The 4 point-probe test revealed that the addition of PAG has increased the conductivity of the NGCs up to 9.7 × 10−3 S.cm−1. The results also showed a remarkable increase in the Young modulus and SEM images revealed that the suggested process could produce NGCs continuously and uniformly with desirable porosity. The Fourier-transform infrared spectroscopy spectrum proved a good interaction between PAG and the polymeric matrix. Furthermore, the addition of PAG slightly prevented biodegradation of the NGCs. Finally, the cell viability assay confirmed... 

    Determining water-oil relative permeability and capillary pressure from steady-state coreflood tests

    , Article Journal of Petroleum Science and Engineering ; Volume 205 , 2021 ; 09204105 (ISSN) Borazjani, S ; Hemmati, N ; Behr, A ; Genolet, L ; Mahani, H ; Zeinijahromi, A ; Bedrikovetsky, P ; Sharif University of Technology
    Elsevier B.V  2021
    This study aims at the simultaneous determination of relative permeability and capillary pressure from steady-state corefloods. Besides using the measurements of pressure-drop across the core and average saturation under steady-state conditions, we use the transient data between the sequential steady states. The inverse algorithm is based on four type curves “stabilizsation period versus water-cut” revealed by asymptotic analysis of the transient solution near end-point saturations, and on the exponential shape of transition data histories observed by direct numerical runs. The transition measurements are approximated in the stabilisation periods by the type curves using non-linear... 

    A laboratory approach to enhance oil recovery factor in a low permeable reservoir by active carbonated water injection

    , Article Energy Reports ; Volume 7 , 2021 , Pages 3149-3155 ; 23524847 (ISSN) Chen, X ; Paprouschi, A ; Elveny, M ; Podoprigora, D ; Korobov, G ; Sharif University of Technology
    Elsevier Ltd  2021
    In this paper, different injectivity scenarios were experimentally investigated in a coreflooding system to observe the efficiency of each method in laboratory conditions. Surfactant flooding, CO2 injection, carbonated water injection (CWI), active carbonated water injection (ACWI), after water flooding were investigated through the coreflooding system. First, it is necessary to optimize the surfactant concentration and then use it in ACWI injection. To do this, linear alkylbenzene sulfonic acid (LABSA) was used as a cationic surfactant at different concentrations. It was observed that 0.6 PV concentration of LABSA had an optimum result as increasing the surfactant concentration would not be... 

    Advancement of sensor integrated organ-on-chip devices

    , Article Sensors (Switzerland) ; Volume 21, Issue 4 , 2021 , Pages 1-44 ; 14248220 (ISSN) Clarke, G.A ; Hartse, B. X ; Niaraki Asli, A. E ; Taghavimehr, M ; Hashemi, N ; Abbasi Shirsavar, M ; Montazami, R ; Alimoradi, N ; Nasirian, V ; Ouedraogo, L. J ; Hashemi, N. N ; Sharif University of Technology
    MDPI AG  2021
    Organ-on-chip devices have provided the pharmaceutical and tissue engineering worlds much hope since they arrived and began to grow in sophistication. However, limitations for their applicability were soon realized as they lacked real-time monitoring and sensing capabilities. The users of these devices relied solely on endpoint analysis for the results of their tests, which created a chasm in the understanding of life between the lab the natural world. However, this gap is being bridged with sensors that are integrated into organ-on-chip devices. This review goes in-depth on different sensing methods, giving examples for various research on mechanical, electrical resistance, and bead-based... 

    On understanding the relation of knowledge and confidence to requirements quality

    , Article 27th International Working Conference on Requirements Engineering: Foundation for Software Quality, REFSQ 2021, 12 April 2021 through 15 April 2021 ; Volume 12685 LNCS , 2021 , Pages 208-224 ; 03029743 (ISSN) ; 9783030731274 (ISBN) Dehghani, R ; Wnuk, K ; Mendez, D ; Gorschek, T ; Ramsin, R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    [Context and Motivation] Software requirements are affected by the knowledge and confidence of software engineers. Analyzing the interrelated impact of these factors is difficult because of the challenges of assessing knowledge and confidence. [Question/Problem] This research aims to draw attention to the need for considering the interrelated effects of confidence and knowledge on requirements quality, which has not been addressed by previous publications. [Principal ideas/results] For this purpose, the following steps have been taken: 1) requirements quality was defined based on the instructions provided by the ISO29148:2011 standard, 2) we selected the symptoms of low qualified... 

    Turbocharged spark-ignition engine performance prediction in various inlet charged air temperatures fueled with gasoline–ethanol blends

    , Article International Journal of Engine Research ; Volume 22, Issue 7 , 2021 , Pages 2233-2243 ; 14680874 (ISSN) Farzam, R ; Jafari, B ; Kalaki, F ; Sharif University of Technology
    SAGE Publications Ltd  2021
    In this research, the effect of alternative fuels and the inlet charged air temperature is numerically investigated on the performance of a turbocharged spark-ignition engine. For this purpose, a one-dimensional engine and turbocharger model is created in an engine simulation and performance analysis software and validated with former experimental results. Then, the model is run with four fuel types, including two gasoline types with different octane numbers and two ethanol–gasoline blend fuels—E25 and E85. In each case, the inlet charged air temperature is changed from cold to hot condition and performance characteristics such as the spark advance timing, brake torque, brake-specific fuel... 

    Distributed transactive framework for congestion management of multiple-microgrid distribution systems

    , Article IEEE Transactions on Smart Grid ; 2021 ; 19493053 (ISSN) Fattaheian Dehkordi, S ; Rajaei, A ; Abbaspour, A ; Fotuhi Firuzabad, M ; Lehtonen, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    The privatization of distribution systems has resulted in the development of multiple-microgrid (multiple-MG) systems where each microgrid independently operates its local resources. Moreover, the high integration of independent distributed energy sources could lead to operational issues such as grid congestion in future distribution systems. Therefore, this paper provides a transactive-based energy management framework to operate multiple-MG distribution systems; while, alleviating grid congestion in a decentralized manner. In this respect, alternating direction method of multipliers (ADMM) is considered to develop an operational framework that copes with distributed nature of multiple-MG... 

    A hybrid scaffold of gelatin glycosaminoglycan matrix and fibrin as a carrier of human corneal fibroblast cells

    , Article Materials Science and Engineering C ; Volume 118 , 2021 ; 09284931 (ISSN) Hajian Foroushani, Z ; Mahdavi salimi, S ; Abdekhodaie, M. J ; Baradaran Rafii, A ; Tabatabei, M. R ; Mehrvar, M ; Sharif University of Technology
    Elsevier Ltd  2021
    A hybrid scaffold of gelatin-glycosaminoglycan matrix and fibrin (FGG) has been synthesized to improve the mechanical properties, degradation time and cell response of fibrin-like scaffolds. The FGG scaffold was fabricated by optimizing some properties of fibrin-only gel and gelatin-glycosaminoglycan (GG) scaffolds. Mechanical analysis of optimized fibrin-only gel showed the Young module and tensile strength of up to 72 and 121 KPa, respectively. Significantly, the nine-fold increase in the Young modulus and a seven-fold increase in tensile strength was observed when fibrin reinforced with GG scaffold. Additionally, the results demonstrated that the degradation time of fibrin was enhanced... 

    The impact of zirconium oxide nanoparticles content on alginate dialdehyde-gelatin scaffolds in cartilage tissue engineering

    , Article Journal of Molecular Liquids ; Volume 335 , 2021 ; 01677322 (ISSN) Ghanbari, M ; Salavati Niasari, M ; Mohandes, F ; Firouzi, Z ; Mousavi, S.-D ; Sharif University of Technology
    Elsevier B.V  2021
    The desire to regenerate and repair native tissues can be immediately performed by multiple tissue engineering procedures. Gelatin and alginate are biocompatible and biodegradable polymers. The addition of ZrO2 nanoparticles (NPs) into the alginate-gelatin hydrogel is considered to improve mechanical and chemical properties. Therefore, nanocomposite hydrogels have been manufactured by the freeze-drying procedure utilizing oxidized alginate-gelatin with ZrO2 NPs as a reinforcement. The fabricated nanocomposite hydrogels were character-ized by FTIR, FESEM, and rheometer. The hydrogels containing a higher ZrO2 NPs content (1.5%) have better mechanical properties than the hydrogels without NPs.... 

    Injectable hydrogels based on oxidized alginate-gelatin reinforced by carbon nitride quantum dots for tissue engineering

    , Article International Journal of Pharmaceutics ; Volume 602 , 2021 ; 03785173 (ISSN) Ghanbari, M ; Salavati Niasari, M ; Mohandes, F ; Sharif University of Technology
    Elsevier B.V  2021
    Stem cell treatment is promising in the various disorders treatment, but its effect is confined by the adverse conditions in the damaged tissues. The utilization of hydrogels has been suggested as a procedure to defeat this issue by developing the engraftment and survival of injected stem cells. Specifically, injectable hydrogels have drawn much attention due to their shape adaptability, ease of use, and the capability to reach body parts that are hard to access. In this study, the thermosensitive injectable hydrogels based on oxidized alginate, gelatin, and carbon nitride quantum dots (CNQDs) have been fabricated for tissue engineering. The mechanical characteristics of the nanocomposite... 

    Multi-User dynamic searchable symmetric encryption with corrupted participants

    , Article IEEE Transactions on Dependable and Secure Computing ; 2021 ; 15455971 (ISSN) Gharehchamani, J ; Wang, Y ; Papadopoulos, D ; Zhang, M ; Jalili, R ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    We study the problem of multi-user dynamic searchable symmetric encryption (DMUSSE) where a data owner stores its encrypted documents on an untrusted remote server and wishes to selectively allow multiple users to access them by issuing keyword search queries. Specifically, we consider the case where some of the users may be corrupted and colluding with the server to extract additional information about the dataset (beyond what they have access to). We provide the first formal security definition for the dynamic setting as well as forward and backward privacy definitions. We then propose SE, the first provably secure DMUSSE scheme and instantiate it in two versions, one based on oblivious... 

    A classification of hadoop job schedulers based on performance optimization approaches

    , Article Cluster Computing ; Volume 24, Issue 4 , 2021 , Pages 3381-3403 ; 13867857 (ISSN) Ghazali, R ; Adabi, S ; Down, D. G ; Movaghar, A ; Sharif University of Technology
    Springer  2021
    Job scheduling in MapReduce plays a vital role in Hadoop performance. In recent years, many researchers have presented job scheduler algorithms to improve Hadoop performance. Designing a job scheduler that minimizes job execution time with maximum resource utilization is not a straightforward task. The primary purpose of this paper is to investigate agents affecting job scheduler efficiency and present a novel classification for job schedulers based on these factors. We provide a comprehensive overview of existing job schedulers in each group, evaluating their approaches, their effects on Hadoop performance, and comparing their advantages and disadvantages. Finally, we provide... 

    Application of mean-covariance regression methods for estimation of edp|im distributions for small record sets

    , Article Journal of Earthquake Engineering ; 2021 ; 13632469 (ISSN) Ghods, B ; Rahimzadeh Rofooei, F ; Sharif University of Technology
    Taylor and Francis Ltd  2021
    The performance of several regression methods is investigated to estimate the distribution of engineering demand parameters conditioned on intensity measures (EDP|IM) for small record sets. In particular, the performance of the multivariate ordinary least squares (OLS), a simultaneous mean-variance regression (MVR) done by a penalized weighted least-square loss function, and a mean-covariance/variance regression based on expectation maximization method (EM) are assessed. The efficiency of the introduced methods is compared with FEMA-P58 methodology. Performance assessment of EM and MVR methods shows that the overall increase in efficiency is about 25–45% for maximum inter-story drift ratios,... 

    Healthy and diseasedin vitromodels of vascular systems

    , Article Lab on a Chip ; Volume 21, Issue 4 , 2021 , Pages 641-659 ; 14730197 (ISSN) Hosseini, V ; Mallone, A ; Nasrollahi, F ; Ostrovidov, S ; Nasiri, R ; Mahmoodi, M ; Haghniaz, R ; Baidya, A ; Salek, M. M ; Darabi, M. A ; Orive, G ; Shamloo, A ; Dokmeci, M. R ; Ahadian, S ; Khademhosseini, A ; Sharif University of Technology
    Royal Society of Chemistry  2021
    Irregular hemodynamics affects the progression of various vascular diseases, such atherosclerosis or aneurysms. Despite the extensive hemodynamics studies on animal models, the inter-species differences between humans and animals hamper the translation of such findings. Recent advances in vascular tissue engineering and the suitability ofin vitromodels for interim analysis have increased the use ofin vitrohuman vascular tissue models. Although the effect of flow on endothelial cell (EC) pathophysiology and EC-flow interactions have been vastly studied in two-dimensional systems, they cannot be used to understand the effect of other micro- and macro-environmental parameters associated with... 

    SELM: Software engineering of machine learning models

    , Article 20th International Conference on New Trends in Intelligent Software Methodologies, Tools and Techniques, SoMeT 2021, 21 September 2021 through 23 September 2021 ; Volume 337 , 2021 , Pages 48-54 ; 09226389 (ISSN); 9781643681948 (ISBN) Jafari, N ; Besharati, M. R ; Hourali, M ; Sharif University of Technology
    IOS Press BV  2021
    One of the pillars of any machine learning model is its concepts. Using software engineering, we can engineer these concepts and then develop and expand them. In this article, we present a SELM framework for Software Engineering of machine Learning Models. We then evaluate this framework through a case study. Using the SELM framework, we can improve a machine learning process efficiency and provide more accuracy in learning with less processing hardware resources and a smaller training dataset. This issue highlights the importance of an interdisciplinary approach to machine learning. Therefore, in this article, we have provided interdisciplinary teams' proposals for machine learning. © 2021... 

    Engineering of CIGS nanoparticle inks for colloidal stability, uniform film formation and application as HTL for perovskite solar cells

    , Article Journal of Industrial and Engineering Chemistry ; 2021 ; 1226086X (ISSN) Khosroshahi, R ; Tehrani, N. A ; Forouzandeh, M ; Behrouznejad, F ; Taghavinia, N ; Bagherzadeh, M ; Sharif University of Technology
    Korean Society of Industrial Engineering Chemistry  2021
    In this work, synthesis of CuIn0.75Ga0.25S2 (CIGS) nanoparticles, the formation of stable dispersion, deposition of high-quality films and, fabrication of thin-film Perovskite solar cells are reported. The stability of nanoparticle ink is crucial in the formation of device-quality films. The chalcogenide-based materials are widely used in thin-film solar cells; in particular, Cu(In,Ga)S2 are used as an absorber and hole transporting layer. In the present study, the nanoparticles of about 20 nm size and bandgap of 1.5 eV are synthesized using a heat-up method. A variety of solvents are used as dispersing media and the stability of the inks is evaluated by precise optical monitoring. We... 

    Optimized age dependent clustering algorithm for prognosis: A case study on gas turbines

    , Article Scientia Iranica ; Volume 28, Issue 3 B , 2021 , Pages 1245-1258 ; 10263098 (ISSN) Mahmoodian, A ; Durali, M ; Abbasian Najafabadi, T ; Saadat Foumani, M ; Sharif University of Technology
    Sharif University of Technology  2021
    This paper proposes an Age-Dependent Clustering (ADC) structure to be used for prognostics. To achieve this aim, a step-by-step methodology is introduced, that includes clustering, reproduction, mapping, and finally estimation of Remaining Useful Life (RUL). In the mapping step, a neural fitting tool is used. To clarify the age-based clustering concept, the main elements of the ADC model is discussed. A Genetic algorithm (GA) is used to find the elements of the optimal model. Lastly, the fuzzy technique is applied to modify the clustering. By investigating a case study on the health monitoring of some turbofan engines, the efficacy of the proposed method is demonstrated. The results showed...