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quality-control
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Total 170 records
DC-link loop bandwidth selection strategy for grid-connected inverters considering power quality requirements
, Article International Journal of Electrical Power and Energy Systems ; Volume 119 , 2020 ; Mokhtari, H ; Ghasemi, M. A ; Peyghami, S ; Davari, P ; Blaabjerg, F ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
DC-link voltage and output current control loops are two cascaded loops in the control structure of grid-connected inverters. A high DC-link voltage loop bandwidth (DCL-BW) provides more disturbance rejection capability for the control loop and is preferred from control system perspective. However, for stability issues, this BW is limited and must be sufficiently less than that of the current control loop. Among the different control schemes, instantaneous active reactive control (IARC) method provides the highest possible DCL-BW (i.e., 0.02 × switching frequency). Having this degree of freedom in the controller design, a proper methodology should be defined for selection of DCL-BW. In this...
Providing multiclass of services in optical CDMA packet networks
, Article 4th IEEE/IFIP International Conference in Central Asia on Internet, ICI 2008, Tashkent, 23 September 2008 through 25 September 2008 ; 2008 ; 9781424422838 (ISBN) ; Pakravan, M. R ; Goudarzi, H ; Sharif University of Technology
2008
Abstract
In this paper we discuss and analyze an enhanced media access control (MAC) layer protocol which uses the signaling method benefits of physical layer in order to provide different quality of service (QoS) levels in optical code-division multiple-access (OCDMA) packet networks. In the proposed network architecture the users are categorized into the high and low classes of service. Users of each class transmit at the same power level and different from the other classes' users. Also, the MAC of each user estimates the amount of interference on the channel and adjusts the packet transmission's time to improve network performance. Through simulation it is shown that the combination of...
The tolerance level of the ecosystem as a limited constrain in the development planning
, Article Ecological Indicators ; Volume 132 , 2021 ; 1470160X (ISSN) ; Saboohi, Y ; Azamian, S ; Sharif University of Technology
Elsevier B.V
2021
Abstract
There are several methods for assessing ecosystem tolerance level, each method is defined according to the target of the ecosystem development. This paper seeks a way to plan for the development of the existing ecosystems modified for human activities. For this purpose, two methods have been applied to assess the effects of local development on the local ecosystem tailored to the different demands. Thus, after gathering data in a coastal region all technologies being capable to be applied in this region regarding ecotourism development (population growth) were determined. Via different indicators, the quality of the ecosystem was evaluated. The Ecosystem Quality Index (EQI) and Technique for...
BOT-MICS: Bounding time using analytics in mixed-criticality systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; 2021 ; 02780070 (ISSN) ; Hosseinghorban, A ; Sahoo, S. S ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
An increasing trend for reducing cost, space, and weight leads to modern embedded systems that execute multiple tasks with different criticality levels on a common hardware platform while guaranteeing a safe operation. In such Mixed-Criticality (MC) systems, multiple Worst-Case Execution Times (WCETs) are defined for each task, corresponding to system operation mode to improve the MC system’s timing behavior at run-time. Determining the appropriate WCETs for lower criticality modes is non-trivial. On the one hand, considering a very low WCET for tasks can improve the processor utilization by scheduling more tasks in that mode, on the other hand, using a larger WCET ensures that the mode...
Highly sensitive voltammetric determination of lamotrigine at highly oriented pyrolytic graphite electrode
, Article Bioelectrochemistry ; Volume 84 , 2012 , Pages 38-43 ; 15675394 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
2012
Abstract
The electrochemical behavior of lamotrigine (LMT) at the pyrolytic graphite electrode (PGE) is investigated in detail by the means of cyclic voltammetry. During the electrochemical reduction of LMT, an irreversible cathodic peak appeared. Cyclic voltammetric studies indicated that the reduction process has an irreversible and adsorption-like behavior. The observed reduction peak is attributed to a two-electron process referring to the reduction of azo group. The electrode showed an excellent electrochemical activity toward the electro-reduction of LMT, leading to a significant improvement in sensitivity as compared to the glassy carbon electrode. The results of electrochemical impedance...
Preparation and biological evaluation of radiolabeled-folate embedded superparamagnetic nanoparticles in wild-type rats
, Article Journal of Radioanalytical and Nuclear Chemistry ; Volume 287, Issue 1 , January , 2011 , Pages 119-127 ; 02365731 (ISSN) ; Hosseini Salekdeh, S. L ; Mahmoudi, M ; Yousefnia, H ; Majdabadi, A ; Pouladian, M ; Sharif University of Technology
2011
Abstract
In this study, superparamagnetic iron oxide nanoparticles (SPION) embedded by folic acid (SPION-folate) were prepared by a modified co-precipitation method. The structure, size, morphology, magnetic property and relaxivity of the SPION-folate were characterized systematically by means of XRD, VSM, HRSEM and TEM and the interaction between folate and iron oxide (Fe3O 4) was characterized by FT-IR. The particle size was shown to be ≈5-10 nm. To ensure biocompatibility, the interaction of these SPION with mouse connective tissue cells (adhesive) was investigated using an MTT assay. Consequently, gallium-67 labeled nanoparticles ([67Ga]-SPION-folate) were prepared using 67Ga with a high labeling...
Multiservice provisioning and quality of service guarantee in WDM optical code switched GMPLS core networks
, Article Journal of Lightwave Technology ; Volume 27, Issue 12 , 2009 , Pages 1754-1762 ; 07338724 (ISSN) ; Salehi, J. A ; Sharif University of Technology
2009
Abstract
In this paper, we propose a new scheme to provide multiservice transmission on generalized multiprotocol label switching (GMPLS) networks using optical code-division multiplexing (OCDM) in each wavelength of a wavelength-division multiplexing system. To provide multiservice transmission in a typical GMPLS network, we propose to classify the fiber bandwidth into a number of waveband and consider the wavelengths of each waveband for a specific class-of-service such that the corresponding codes to be used are designed based on the characteristics of the class-of-service. The traffic behavior of the network is examined using Erlang's model, and the probability density functions (PDF) of the...
Gas chromatographic fingerprint analysis of secondary metabolites of Stachys lanata (Stachys byzantine C. Koch) combined with antioxidant activity modelling using multivariate chemometric methods
, Article Journal of Chromatography A ; Volume 1602 , 2019 , Pages 432-440 ; 00219673 (ISSN) ; Abtahi, M ; Parastar, H ; Sharif University of Technology
Elsevier B.V
2019
Abstract
S. lanata has been traditionally used as a medicinal plant due to its various biological activities such as antioxidant activity. Therefore, identification and quality control studies of this plant are of great importance. To this end, gas chromatography (GC) combined with chemometrics was proposed for fingerprint analysis of S. lanata samples. This study sought to classify GC fingerprints of twenty-eight S. lanata samples from eight different regions of Iran and more importantly, to correlate fingerprints to the antioxidant activity to select S. lanata volatile antioxidant markers. S. lanata samples were classified into five and three classes using partial least squares-discriminant...
Public ingestion exposure to 226Ra in Ramsar, Iran
, Article Journal of Environmental Radioactivity ; Volume 198 , 2019 , Pages 11-17 ; 0265931X (ISSN) ; Salehi, A. A ; Naddafi, K ; Kardan, M. R ; Yunesian, M ; Nodehi, R. N ; Deevband, M. R ; Shooshtari, M. G ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Ramsar, in the north of Iran by the Caspian Sea, has been known for the highest natural radiation background on Earth due to the local geology and hydrogeology. The residents and visitors use the hot springs that distribute the natural radionuclides especially 226Ra and its decay products in the areas. Many studies have been undertaken to measure the absorbed dose rate in Ramsar's air, however, no survey has been done to assess public internal exposure from ingestion of natural radionuclides, such as, a broad survey for 226Ra was conducted in foodstuffs and drinking water. This study presents the results of public annual activity intake (Bq) and effective dose (μSv) from ingestion of 226Ra...
A strategic management model for evaluation of health, safety and environmental performance
, Article Environmental Monitoring and Assessment ; Volume 184, Issue 5 , 2012 , Pages 2981-2991 ; 01676369 (ISSN) ; Toutounchian, S ; Roayaei, E ; Nassiri, P ; Sharif University of Technology
Abstract
Strategic health, safety, and environmental management system (HSE-MS) involves systematic and cooperative planning in each phase of the lifecycle of a project to ensure that interaction among the industry group, client, contractor, stakeholder, and host community exists with the highest level of health, safety, and environmental standard performances. Therefore, it seems necessary to assess the HSE-MS performance of contractor(s) by a comparative strategic management model with the aim of continuous improvement. The present Strategic Management Model (SMM) has been illustrated by a case study and the results show that the model is a suitable management tool for decision making in a contract...