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systems-engineering
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Management of System Requirements in Systems Engineering Process with Axiomatic Design Principles
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor)
Abstract
Functional Requirements (FR) are traditionally known to be "input" as far as an engineering process is concerned. However, for a Systems Engineer (SE), this is not the case. A well-known task of a SE is, in fact, to develop FRs from what is considered as the customer needs. The traditional approach to develop suitable FRs involves an algorithmic procedure; which mostly relies on the skills, knowledge, attitude, and experiences of the SE or experts members of design team. It is therefore an ad-hoc method which results in quite a few numbers of trial-errors and its effectiveness only reveals itself as time goes on. The current work aims to address such a shortcoming in Systems Engineering...
Study of Adaptable Organizational Structures for Entering International Protocols Case Study: Carbon Trade
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor) ; Kaymaram, Farid (Supervisor)
Abstract
In this research a systemic framework for recognizing and using international opportunities has been generated based on the Viable System Model (VSM). This framework consists of designing required functions, recognizing capabilities and assigning requirements in the different levels of the system. Based on this framework a systemic analysis for diagnosing Iran’s problems and barriers in implementing Clean Development Mechanism (CDM) which is a part of international carbon trade has been done. This research results show that the generated systemic framework has a good diagnosing power for identifying systemic problems in different systems
Proposing a Control Method for Influenza Disease
, M.Sc. Thesis Sharif University of Technology ; Shahrokhi, Mohammad (Supervisor)
Abstract
Immediate control of pandemic influenza to avoid casualties and financial losses is an important issue. In this thesis, two types of controllers including optimal controller and adaptive generalized predictive controller based on linear input-output model, with vaccine, treatment and quarantine being controlling variables, have been used to control influenza. Each controlling methods were investigated for different states including single-input single-output and multi-input single-output. Single-input single-output and multi-input single-output models are identified as online and offline using least squares method. Since it is difficult to exactly identify the model parameters, especially at...
Model predictive control of nonlinear discrete time systems with guaranteed stability
, Article Asian Journal of Control ; 2018 ; 15618625 (ISSN) ; Haeri, M ; Sharif University of Technology
Wiley-Blackwell
2018
Abstract
This paper presents the design of a new robust model predictive control algorithm for nonlinear systems represented by a linear model with unstructured uncertainty. The linear model is obtained by linearizing the nonlinear system at an operating point and the difference between the nonlinear and linear model is considered as a Lipschitz nonlinear function. The controller is designed for the linear model, which fulfills the stabilization condition for the nonlinear term. Unlike previous studies that have not considered a valid Lipschitz matrix of nonlinear term in the design process, we propose an algorithm in this paper in which it is considered. Therefore, the closed loop stability of the...
Model predictive control of nonlinear discrete time systems with guaranteed stability
, Article Asian Journal of Control ; Volume 22, Issue 2 , 2020 , Pages 657-666 ; Haeri, M ; Sharif University of Technology
Wiley-Blackwell
2020
Abstract
This paper presents the design of a new robust model predictive control algorithm for nonlinear systems represented by a linear model with unstructured uncertainty. The linear model is obtained by linearizing the nonlinear system at an operating point and the difference between the nonlinear and linear model is considered as a Lipschitz nonlinear function. The controller is designed for the linear model, which fulfills the stabilization condition for the nonlinear term. Unlike previous studies that have not considered a valid Lipschitz matrix of nonlinear term in the design process, we propose an algorithm in this paper in which it is considered. Therefore, the closed loop stability of the...
CFD aided procedure for optimizing electrical mobility spectrometer
, Article Defect and Diffusion Forum ; Volume 366 , 2016 , Pages 73-87 ; 10120386 (ISSN) ; Shaygani, A ; Sani, M ; Saidi, M. S ; Sharif University of Technology
Trans Tech Publications Ltd
Abstract
Aerosol measurement is used in a variety of fields such as nanotechnology, materials science, pollution monitoring, air quality measurements, combustion and engine exhaust analysis, inhalation toxicology, and medical studies. One of the most prevalent methods for aerosol measurement is to use electrical mobility. An electrical mobility spectrometer (EMS) is used to measure aerosol particles size distribution ranging from 10-1000 nanometers, under the influence of an electric field. The accuracy of this distribution is influenced by flow conditions, the geometry of the EMS, the electric field, and the number of electrode rings. In this work, a multi-channel EMS is studied using computational...
Modified branching process for the reliability analysis of complex systems: Multiple-robot systems
, Article Communications in Statistics - Theory and Methods ; Volume 47, Issue 7 , 2018 , Pages 1641-1652 ; 03610926 (ISSN) ; Akhavan Niaki, S. T ; Sharif University of Technology
Taylor and Francis Inc
2018
Abstract
Current design practice is usually to produce a safety system which meets a target level of performance that is deemed acceptable by the regulators. Safety systems are designed to prevent or alleviate the consequences of potentially hazardous events. In many modern industries the failure of such systems can lead to whole system breakdown. In reliability analysis of complex systems involving multiple components, it is assumed that the components have different failure rates with certain probabilities. This leads into extensive computational efforts involved in using the commonly employed generating function (GF) and the recursive algorithm to obtain reliability of systems consisting of a...
Online Near-Optimal Path Planning to Back-up Aircraft Mission Capabilities in Emergency Conditions
, Article Advances in Intelligent Systems and Computing, 19 August 2014 through 21 August 2014, Las Vegas, NV ; Volume 1089 , August , 2015 , Pages 17-24 ; 21945357 (ISSN) ; 9783319084213 (ISBN) ; Shadram, Z ; ALDEC; NV Energy; University of Nevada Las Vegas (UNLV) ; Sharif University of Technology
Springer Verlag
2015
Abstract
This work presents a novel approach to redefine a "Safe Aircraft" based on systems engineering fundamentals. We aim todemonstrate the possibility as well as suitability of the "Functional-Aircraft" instead of currently employed concept of "Physically-defined-Safe-Aircraft". The current work is consistent with ever-increasing number of flights; as it suggests that any aircraft that can complete its mission should not declare emergencies due to any physical malfunction. With proper simulations, wedemonstrate the feasibility of "Functionally Safe" concept as oppose to the "Physically Safe" aircraft. The process revolves around standard and well-known documents such as FTA and FMEA; which are...
Optimal energy management strategy of a hybrid electric vehicle considering engine noise
, Article JVC/Journal of Vibration and Control ; Volume 24, Issue 23 , 2018 , Pages 5546-5555 ; 10775463 (ISSN) ; Khademnahvi, M ; Delkhosh, M ; Sharif University of Technology
SAGE Publications Inc
2018
Abstract
Noise emission from vehicles in urban transportation has become of interest for researchers in addition to the engine exhaust gas emissions due to its significant effect on public health. In this work, an optimal energy management strategy is proposed for a hybrid electric vehicle (HEV) by taking the effect of engine noise into account. The engine noise is calculated based on a pressure-based combustion noise model at different operating points of a 1.5 L gasoline engine. The optimal operating points of the engine are defined using the calculated engine noise from in-cylinder pressure data and experimental data of brake specific fuel consumption (FC). A modification on the electric assist...
Effecive & efficient DSM configuration guidelines for low-cost development of complex systems
, Article Gain Competitive Advantage by Managing Complexity - Proceedings of the 14th International Dependency and Structure Modelling Conference, DSM 2012, 13 September 2012 through 14 September 2012 ; 2012 , Pages 125-137 ; 9783446433540 (ISBN) ; Sharif University of Technology
Institution of Engineering Designers
2012
Abstract
With the proliferation of more complex systems has come the need to find better solutions in both technical and management domains. Such complex systems are usually larger in size, have more parallel operations and contain more complex interfaces (Eisner, 2005). The Design Structure Matrix is a very useful tool in handling such complexities, provided that the system designer can use it properly. This paper addresses how effectiveness & efficiency are defined for a DSM and how these two important characteristics can be achieved. The importance of understanding the solution space in constructing an effective & efficient DSM is discussed and general guidelines are given on configuring the DSM...
Optimal decision making for orbit transfer system of a student micro-satellite, using multi-criteria decision making
, Article 1st IEEE International Symposium on Systems Engineering, ISSE 2015 - Proceedings, 28 September 2015 through 30 September 2015 ; 2015 , Pages 29-33 ; 9781479919208 (ISBN) ; Mahrooz, M. H ; Rahmani, S ; IEEE Systems Council ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
One of the most important aspects of a successful space mission is the transition to the correct orbit and maintaining it. As a result, many modern orbit transfer techniques have been developed in space industry in order to accomplish this task in a more reliable and less expensive way. However, when it comes to the design of student satellites, usually there are serious limitations on the financial resources, technical database and satellite industry experts. These limitations may compromise the access to advanced methods and techniques. Therefore, reliability and expenses may no longer be the only criteria to be met in the process of design. As a result, at each step of the design, a...
A scalable dependability scheme for routing fabric of SRAM-based reconfigurable devices
, Article IEEE Transactions on Very Large Scale Integration (VLSI) Systems ; Volume 23, Issue 9 , August , 2015 , Pages 1868-1878 ; 10638210 (ISSN) ; Asadi, H ; Khaleghi, B ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
With the continual scaling of feature size, system failure due to soft errors is getting more frequent in CMOS technology. Soft errors have particularly severe effects in static random-access memory (SRAM)-based reconfigurable devices (SRDs) since an error in SRD configuration bits can permanently change the functionality of the system. Since interconnect resources are the dominant contributor to the overall configuration memory upsets in SRD-based designs, the system failure rate can be significantly reduced by mitigating soft errors in routing fabric. This paper first presents a comprehensive analysis of SRD switch box susceptibility to short and open faults. Based on this analysis, we...
Designing a LQR controller for an electro-hydraulic-actuated-clutch model
, Article Proceedings of 2016 2nd International Conference on Control Science and Systems Engineering, ICCSSE 2016, 27 July 2016 through 29 July 2016 ; 2016 , Pages 82-87 ; 9781467398725 (ISBN) ; Selk Ghafari, A ; Pourebrahim, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
During the past decade, Electro-Hydraulic system has performed a significant role in industrial engineering as an actuator for high performance and precision positioning applications. In this case, many control methods have been developed for an electro-hydraulic actuated clutch. In this paper a Linear Quadratic Regulators (LQR) is proposed to trajectory control of a wet clutch actuated by a hydraulic servo valve mechanism. Simulation study was performed using linearized mathematical model of the system implemented in MATLAB software. Based on the simulation results performance of the proposed controller was evaluated and discussed
Fault-tolerant DC power distribution unit based on nonexclusive redundant modules
, Article IEEE Transactions on Industrial Electronics ; Volume 63, Issue 11 , 2016 , Pages 6801-6811 ; 02780046 (ISSN) ; Parvari, R ; Kaboli, S ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Abstract
Reliability of the power distribution unit (PDU) is very important in electrical systems. Since any failure in this unit leads to system failure. A commonly used method for increasing the reliability of a dc PDU is using the redundant modules. If a fault occurs in a voltage regulator of PDU, it is replaced by its redundant module. In conventional redundancy, each dc voltage regulator has its exclusive redundant modules. Therefore, if both a regulator and its redundant modules fail, the system is stopped. It is an important drawback since the exclusive redundant modules of other voltage regulators may not be used, but, the PDU cannot use them instead of faulty regulators. In this paper, the...
Simultaneous management of peak-power and reliability in heterogeneous multicore embedded systems
, Article IEEE Transactions on Parallel and Distributed Systems ; Volume 31, Issue 3 , 2020 , Pages 623-633 ; Saber Latibari, J ; Pasandideh, M ; Ejlali, A ; Sharif University of Technology
IEEE Computer Society
2020
Abstract
Analysis of reliability, power, and performance at hardware and software levels due to heterogeneity is a crucial requirement for heterogeneous multicore embedded systems. Escalating power densities have led to thermal issues for heterogeneous multicore embedded systems. This paper proposes a peak-power-aware reliability management scheme to meet power constraints through distributing power density on the whole chip such that reliability targets are satisfied. In this paper, we consider peak power consumption as a system-level power constraint to prevent system failure. To balance the power consumption, we also employ a Dynamic Frequency Scaling (DFS) method to further reduce peak power...
Performance analysis of SLTC - A table path, low overhead, truthful, and cost efficient routing protocol in MANETs with selfish nodes
, Article 3rd IEEE Asia-Pacific Services Computing Conference, APSCC 2008, Yilan, 9 December 2008 through 12 December 2008 ; 2008 , Pages 243-250 ; 9780769534732 (ISBN) ; Mousavi, H ; Movaghar, A ; Sharif University of Technology
IEEE Computer Society
2008
Abstract
In New applications of Mobile Ad hoc Networks (MANETs), nodes may decide not to cooperate in routing protocols in order to save their limited resources while still using the network to relay their own traffic. Exhibiting such a selfish behavior by even a few nodes may degrade network performance and other cooperating nodes may find themselves unfairly loaded. To cope with such a situation, we propose a Stable path, Low overhead, Truthful, and Cost efficient (SLTC) routing protocol which stimulates nodes to cooperate and act truthfully by utilizing the game theoretic notion of mechanism design. To the best of our knowledge, SLTC is the first protocol attaining the message complexity of O(nd),...
Finding feasible timetables with particle swarm optimization
, Article Innovations'07: 4th International Conference on Innovations in Information Technology, IIT, Dubai, 18 November 2007 through 20 November 2007 ; 2007 , Pages 387-391 ; 9781424418411 (ISBN) ; Najafi Ardabifi, A ; Moeinzadeh, M. H ; Sharifian R, S ; Asgarian, E ; Mohammadzadeh, J ; Sharif University of Technology
IEEE Computer Society
2007
Abstract
A Timetabling problem is usually defined as assigning a set of events to a number of rooms and timeslots such that they satisfy a number of constraints. Particle swarm optimization (PSO) is a stochastic, population-based computer problem-solving algorithm; it is a kind of swarm intelligence that is based on social-psychological principles and provides insights into social behavior, as well as contributing to engineering applications. This paper applies the Particle Swarm Optimization algorithm to the classic Timetabling problem. This is inspired by similar attempts belonging to the evolutionary paradigm in which the metaheuristic involved is tweaked to suit the grouping nature of problems...
Optimal resilience-oriented microgrid formation considering failure probability of distribution feeders
, Article Electric Power Systems Research ; Volume 209 , 2022 ; 03787796 (ISSN) ; Hajipour, E ; Ehsan, M ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
After a natural disaster, there is an urgent need to supply critical loads such as hospitals as soon as possible. Microgrid (MG) formation is one of the quickest ways to achieve this goal. However, in MG formation studies, there is a trade-off between maximizing the amount of restored loads and minimizing their risk of interruption due to the following aftershocks. For the former objective, the minimum number of MGs should be formed, whereas, for the latter objective, the maximum number of MGs should be configured. This paper tackles this contradictory situation by considering the failure risk of distribution feeders in its proposed optimization framework. In this paper, at first, a novel...
Dispersion-division multiple access: A temporal holography-based method
, Article Optik ; Volume 269 , 2022 ; 00304026 (ISSN) ; Kavehvash, Z ; Sharif University of Technology
Elsevier GmbH
2022
Abstract
Multiple access methods are the backbone of today's most communication systems. Increasing the efficiency of these schemes is a challenging engineering task. This paper introduces dispersion-division multiple access, a novel multiple-access technique that can improve the efficiency of multiple-access communication systems. When two (or more) pulses experience different Group Delay Dispersion (GDD) values on a propagation medium, they can be synchronized to overlap in time for combining the phase and amplitude of those pulses. This paper suggests the recoverability of these pulses while being mixed in the transmitter by propagating the combined pulse in a negative Group Velocity Dispersion...
Latecomer firm strategies in complex product systems (CoPS): The case of Iran's thermal electricity generation systems
, Article Research Policy ; Volume 44, Issue 6 , July , 2015 , Pages 1240-1251 ; 00487333 (ISSN) ; Hobday, M ; Hamedi, M ; Sharif University of Technology
Elsevier
2015
Abstract
This paper examines the strategies of a local supplier of high technology capital goods (or complex product systems, CoPS) in a middle-income developing economy, Iran, in its efforts to acquire technology and catch up with market leaders. The study draws upon both the development and business strategy literatures to develop a novel conceptual framework of latecomer strategy which is then applied to the Iranian firm engaged in the design, production and implementation of electricity generation systems. Although exploratory, the study shows that the firm was able to exploit its linkages with local clients, favorable government policies and a growing domestic demand to overcome barriers to...