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Improving the Maintenance Productivity of RAJA Passenger Train CO
, M.Sc. Thesis Sharif University of Technology ; Kumar, Edi (Supervisor) ; Barabadi, Javad (Supervisor)Customer Relationship Management : Concept, Strategy, and Tools
, Book ; Reinartz, Werner
Springer
2018
Quality-of-Service Aware Design and Management of Embedded Mixed-Criticality Systems
, Ph.D. Dissertation Sharif University of Technology ; Ejlali, Alireza (Supervisor) ; Kumar, Akash (Supervisor)
Abstract
Nowadays, implementing a complex system, which executes various applications with different levels of assurance, is a growing trend in modern embedded real- time systems to meet cost, space, timing, and power consumption requirements. Medical devices, automotive, and avionics industries are the most common safety- critical applications, exploiting these systems known as Mixed-Criticality (MC) systems. MC applications are real-time, and to ensure the correctness of these applications, it is essential to meet strict timing requirements as well as functional specifications. The correct design of such MC systems requires a thorough understanding of the system’s functions and their importance to...
Online peak power and maximum temperature management in multi-core mixed-criticality embedded systems
, Article 22nd Euromicro Conference on Digital System Design, DSD 2019, 28 August 2019 through 30 August 2019 ; 2019 , Pages 546-553 ; 9781728128610 (ISBN) ; Nguyen, T. D. A ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
In this work, we address peak power and maximum temperature in multi-core Mixed-Criticality (MC) systems. In these systems, a rise in peak power consumption may generate more heat beyond the cooling capacity. Additionally, the reliability and timeliness of MC systems may be affected due to excessive temperature. Therefore, managing peak power consumption has become imperative in multi-core MC systems. In this regard, we propose an online peak power management heuristic for multi-core MC systems. This heuristic reduces the peak power consumption of the system as much as possible during runtime by exploiting dynamic slack and Dynamic Voltage and Frequency Scaling (DVFS). Specifically, our...
Feasibility of using bulk metallic glass for self-expandable stent applications
, Article Journal of Biomedical Materials Research - Part B Applied Biomaterials ; Volume 105, Issue 7 , 2017 , Pages 1874-1882 ; 15524973 (ISSN) ; Jafary Zadeh, M ; Tavakoli, R ; Cui, F ; Sharif University of Technology
2017
Abstract
Self-expandable stents are widely used to restore blood flow in a diseased artery segment by keeping the artery open after angioplasty. Despite the prevalent use of conventional crystalline metallic alloys, for example, nitinol, to construct self-expandable stents, new biomaterials such as bulk metallic glasses (BMGs) are being actively pursued to improve stent performance. Here, we conducted a series of analyses including finite element analysis and molecular dynamics simulations to investigate the feasibility of using a prototypical Zr-based BMG for self-expandable stent applications. We model stent crimping of several designs for different percutaneous applications. Our results indicate...
Power-Aware run-time scheduler for mixed-criticality systems on multi-core platform
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; 2020 ; Nguyen, T. D. A ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In modern multi-core Mixed-Criticality (MC) systems, a rise in peak power consumption due to parallel execution of tasks with maximum frequency, specially in the overload situation, may lead to thermal issues, which may affect the reliability and timeliness of MC systems. Therefore, managing peak power consumption has become imperative in multi-core MC systems. In this regard, we propose an online peak power and thermal management heuristic for multi-core MC systems. This heuristic reduces the peak power consumption of the system as much as possible during runtime by exploiting dynamic slack and per-cluster Dynamic Voltage and Frequency Scaling (DVFS). Specifically, our approach examines...
Reliability centered maintenance for rolling stock: a case study in coaches' wheel sets of passenger trains of Iranian railway
, Article 2008 IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 2008, Singapore, 8 December 2008 through 11 December 2008 ; 2008 , Pages 516-520 ; 9781424426300 (ISBN) ; Valibeigloo, M ; Asghari, M ; Barabady, J ; Kumar, U ; Sharif University of Technology
2008
Abstract
Historically, most of the maintenance tasks in rolling stock companies are devoted to Preventive Maintenance which leads to some problems such as erroneous maintenance work, unnecessary maintenance tasks, etc. Therefore, it is essential to develop effective maintenance strategies to deal with these problems. While the safety is a significant factor in rolling stock industries, the most well known and widely applied maintenance optimization strategy is so called Reliability Centered Maintenance (RCM). The aim of this paper is to discuss the implementation of RCM to make maintenance of rolling stock of the Raja Passenger Train Corporation more cost effective. Therefore, the paper presents RCM...
Learning-Oriented QoS- and drop-aware task scheduling for mixed-criticality systems
, Article Computers ; Volume 11, Issue 7 , 2022 ; 2073431X (ISSN) ; Alikhani, H ; Safaei, B ; Ejlali, A ; Kumar, A ; Sharif University of Technology
MDPI
2022
Abstract
In Mixed-Criticality (MC) systems, multiple functions with different levels of criticality are integrated into a common platform in order to meet the intended space, cost, and timing requirements in all criticality levels. To guarantee the correct, and on-time execution of higher criticality tasks in emergency modes, various design-time scheduling policies have been recently presented. These techniques are mostly pessimistic, as the occurrence of worst-case scenario at run-time is a rare event. Nevertheless, they lead to an under-utilized system due to frequent drops of Low-Criticality (LC) tasks, and creation of unused slack times due to the quick execution of high-criticality tasks....
Power-Aware runtime scheduler for mixed-criticality systems on multicore platform
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 40, Issue 10 , 2021 , Pages 2009-2023 ; 02780070 (ISSN) ; Nguyen, T. D. A ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
In modern multicore mixed-criticality (MC) systems, a rise in peak power consumption due to parallel execution of tasks with maximum frequency, specially in the overload situation, may lead to thermal issues, which may affect the reliability and timeliness of MC systems. Therefore, managing peak power consumption has become imperative in multicore MC systems. In this regard, we propose an online peak power and thermal management heuristic for multicore MC systems. This heuristic reduces the peak power consumption of the system as much as possible during runtime by exploiting dynamic slack and per-cluster dynamic voltage and frequency scaling (DVFS). Specifically, our approach examines...
Toward the design of fault-tolerance-and peak-power-aware multi-core mixed-criticality systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; 2021 ; 02780070 (ISSN) ; Hosseinghorban, A ; Salehi, M ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Mixed-Criticality (MC) systems have recently been devised to address the requirements of real-time systems in industrial applications, where the system runs tasks with different criticality levels on a single platform. In some workloads, a highcritically task might overrun and overload the system, or a fault can occur during the execution. However, these systems must be fault-tolerant and guarantee the correct execution of all highcriticality tasks by their deadlines to avoid catastrophic consequences, in any situation. Furthermore, in these MC systems, the peak power consumption of the system may increase, especially in an overload situation and exceed the processor Thermal Design Power...
Toward the design of fault-tolerance-aware and peak-power-aware multicore mixed-criticality systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 41, Issue 5 , 2022 , Pages 1509-1522 ; 02780070 (ISSN) ; Hosseinghorban, A ; Salehi, M ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
Mixed-criticality (MC) systems have recently been devised to address the requirements of real-time systems in industrial applications, where the system runs tasks with different criticality levels on a single platform. In some workloads, a high-critically task might overrun and overload the system, or a fault can occur during the execution. However, these systems must be fault tolerant and guarantee the correct execution of all high-criticality (HC) tasks by their deadlines to avoid catastrophic consequences, in any situation. Furthermore, in these MC systems, the peak-power consumption of the system may increase, especially in an overload situation and exceed the processor thermal design...
BOT-MICS: Bounding time using analytics in mixed-criticality systems
, Article IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems ; Volume 41, Issue 10 , 2022 , Pages 3239-3251 ; 02780070 (ISSN) ; Hosseinghorban, A ; Sahoo, S. S ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
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 the system operation mode to improve the MC system's timing behavior at runtime. Determining the appropriate WCETs for lower criticality (LC) modes is nontrivial. 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...
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...
Improving the timing behaviour of mixed-criticality systems using chebyshev's theorem
, Article 2021 Design, Automation and Test in Europe Conference and Exhibition, DATE 2021, 1 February 2021 through 5 February 2021 ; Volume 2021-February , 2021 , Pages 264-269 ; 15301591 (ISSN); 9783981926354 (ISBN) ; Hoseinghorban, A ; Sahoo, S. S ; Ejlali, A ; Kumar, A ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
In Mixed-Criticality (MC) systems, there are often multiple Worst-Case Execution Times (WCETs) for the same task, corresponding to system operation mode. Determining the appropriate WCETs for lower criticality modes is non-trivial; while on the one hand, a low WCET for a mode can improve the processor utilization in that mode, on the other hand, using a larger WCET ensures that the mode switches are minimized, thereby maximizing the quality-of-service for all tasks, albeit at the cost of processor utilization. Although there are many studies to determine WCET in the highest criticality mode, no analytical solutions are proposed to determine WCETs in other lower criticality modes. In this...
Clay-plug sediment as the locus of arsenic pollution in Holocene alluvial-plain aquifers
, Article Catena ; Volume 202 , 2021 ; 03418162 (ISSN) ; Ghosh, D ; Donselaar, M. E ; Burgers, F ; Ghosh, A. K ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Shallow aquifers in many Holocene alluvial basins around the world have in the last three decades been identified as arsenic pollution hotspots, in which the spatial variation of natural (or: geogenic) arsenic concentration is conditioned by the meandering-river geomorphology and the fluvial lithofacies distribution. Despite the large amount of publications on the specifics of the pollution, still many uncertainties remain as to the provenance and processes that lead to arsenic enrichment in aquifers. In this paper, arsenic in abandoned and sediment-filled meandering-river bends (or: clay-plugs) is highlighted as a primary source of aquifer pollution. The combination of high organic-carbon...
Visualising structural modification of patterned graphene nanoribbons using tip-enhanced Raman spectroscopy
, Article Chemical Communications ; Volume 57, Issue 56 , 2021 , Pages 6895-6898 ; 13597345 (ISSN) ; Esfandiar, A ; Lancry, O ; Shao, J ; Kumar, N ; Chaigneau, M ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
Graphene nanoribbons (GNRs) fabricated using electron beam lithography are investigated using tip-enhanced Raman spectroscopy (TERS) with a spatial resolution of 5 nm under ambient conditions. High-resolution TERS imaging reveals a structurally modified 5-10 nm strip of disordered graphene at the edge of the GNRs. Furthermore, hyperspectral TERS imaging discovers the presence of nanoscale organic contaminants on the GNRs. These results pave the way for nanoscale chemical and structural characterisation of graphene-based devices using TERS. © The Royal Society of Chemistry 2021
Exergy and economic analysis of solar chimney in iran climate: tehran, semnan, and bandar abbas
, Article Mathematical Modelling of Engineering Problems ; Volume 7, Issue 1 , 2020 , Pages 55-67 ; Mohammadi, O ; Sadeghzadeh, M ; Pourfayaz, F ; Kumar, R ; Lorenzini, G ; Sharif University of Technology
International Information and Engineering Technology Association
2020
Abstract
Solar chimney is one of the attractive approaches to produce power from a clean source of renewable energy. In this investigation, a potentiometric study is carried out to find out a best location for construction of a solar chimney in different climates of Iran, in the Middle East. With this objective, three locations with different weather climates were chosen, i.e. Tehran, Semnan, and Bandar Abbas. These locations were chosen due to their different climatic conditions and solar irradiation. The used weather conditions are extracted for the middle day of summer, 6th August. The output power of the solar chimney plant was assessed as a function of various thermo-physical properties such as...
Stereolithography 3D bioprinting method for fabrication of human corneal stroma equivalent
, Article Annals of Biomedical Engineering ; Volume 48, Issue 7 , June , 2020 , Pages 1955-1970 ; Abdekhodaie, M. J ; Kumar, H ; Mashayekhan, S ; Baradaran Rafii, A ; Kim, K ; Sharif University of Technology
Springer
2020
Abstract
Abstract: 3D bioprinting technology is a promising approach for corneal stromal tissue regeneration. In this study, gelatin methacrylate (GelMA) mixed with corneal stromal cells was used as a bioink. The visible light-based stereolithography (SLA) 3D bioprinting method was utilized to print the anatomically similar dome-shaped structure of the human corneal stroma. Two different concentrations of GelMA macromer (7.5 and 12.5%) were tested for corneal stroma bioprinting. Due to high macromer concentrations, 12.5% GelMA was stiffer than 7.5% GelMA, which made it easier to handle. In terms of water content and optical transmittance of the bioprinted scaffolds, we observed that scaffold with...
An identity based authentication protocol for smart grid environment using physical uncloneable function
, Article IEEE Transactions on Smart Grid ; Volume 12, Issue 5 , 2021 , Pages 4426-4434 ; 19493053 (ISSN) ; Qadri, S ; Shamshad, S ; Faizan Ayub, M ; Mahmood, K ; Kumar, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Smart grid plays an important role in managing demand response management in modern smart city using Information and Communication Technologies (ICTs). In smart grid environment, sensors are widely used for surveillance. These are deployed on the high tension power supply lines which help to share the information to control center about line breakage or any other flaw. Besides the cyber-attacks, sensors may also experience physical attacks as they are deployed on high-tension power lines in an open environment. Moreover, an attacker can also impersonate the information exchanged between sensors, gateways and control centers. Therefore, the most indispensable requirement is to prevent these...
Review - Textile based chemical and physical sensors for healthcare monitoring
, Article Journal of the Electrochemical Society ; Volume 167, Issue 3 , 2020 ; Angizi, S ; Kumar, S ; Pandey, C. M ; Simchi, A ; Willander, M ; Malhotra, B. D ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
The emergence of textile-based wearable sensors as light-weight portable devices to monitor desired parameters, has recently gained much interest and has led to the development of flexible electronics on non-rigid substrates. The flexible biosensors may result in improved sports performance, to monitor the desired bodies for injuries, improved clinical diagnostics and monitor biological molecules and ions in biological fluids such as saliva, sweat. In addition, they could help users with different types of disorders such as blindness. In this context, new composite and nanomaterials have been found to be promising candidates to obtain improved performance of the textile based wearable...