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systems-engineering
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Performance evaluation of communication networks for parallel and distributed systems
, Article Parallel Computing ; Volume 32, Issue 11-12 , 2006 , Pages 775-776 ; 01678191 (ISSN) ; Ould Khaoua, M ; Zomaya, A. Y ; Sharif University of Technology
2006
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...
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...
Applying the system engineering approach to devise a master's degree program in space technology in developing countries
, Article 60th International Astronautical Congress 2009, IAC 2009, Daejeon, 12 October 2009 through 16 October 2009 ; Volume 10 , 2009 , Pages 8365-8376 ; 9781615679089 (ISBN) ; Tabeshian, M ; Taheran Vernoosfaderani, M ; Sharif University of Technology
2009
Abstract
Although more than half a century is passed since space technology was first developed, developing countries are just beginning to enter the arena, focusing mainly on educating professionals. Space technology by itself is an interdisciplinary science, is costly, and developing at a fast pace. Moreover, a fruitful education system needs to remain dynamic if the quality of education is the main concern, making it a complicated system. This paper makes use of the System Engineering Approach and the experiences of developed countries in this area while incorporating the needs of the developing countries to devise a comprehensive program in space engineering at the Master's level. The needs of...
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...
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...
A low energy soft error-tolerant register file architecture for embedded processors
, Article 11th IEEE High Assurance Systems Engineering Symposium, HASE 2008, Nanjing, 3 December 2008 through 5 December 2008 ; December , 2008 , Pages 109-116 ; 15302059 (ISSN); 9780769534824 (ISBN) ; Ahmadian, S. N ; Miremadi, S. G ; Nanjing University; IEEE Computer Society; IEEE Reliability Society ; Sharif University of Technology
2008
Abstract
This paper presents a soft error-tolerant architecture to protect embedded processors register files. The proposed architecture is based on selectively duplication of the most vulnerable registers values in a cache memory embedded beside the processor register file so called register cache. To do this, two parity bits are added to each register of the processor to detect up to three contiguous errors. To recover the erroneous register value, two distinct cache memories are utilized for storing the redundant copy of the vulnerable registers, one for short lived registers and the other one for long lived registers. The proposed method has two key advantageous as compared to fully ECC protected...
The 2D DBM: an attractive alternative to the simple 2D mesh topology for On-Chip networks
, Article 26th IEEE International Conference on Computer Design 2008, ICCD, Lake Tahoe, CA, 12 October 2008 through 15 October 2008 ; 2008 , Pages 486-490 ; 9781424426584 (ISBN) ; Modarressi, M ; Sarbazi Azad, H ; Sharif University of Technology
2008
Abstract
During the recent years, 2D mesh network-onchip has attracted much attention due to its suitability for VLSI implementation. The 2-dimensional de Bruijn topology for network-on-chip is introduced in this paper as an attractive alternative to the popular simple 2D mesh NoC. Its cost is equal to that of the simple 2D mesh but it has a logarithmic diameter. We compare the proposed network and the popular mesh network in terms of power consumption and network performance. Compared to the equal sized simple mesh NoC, the proposed de Bruijn-based network has better performance while consuming less energy. © 2008 IEEE
Economic batch quantity with setup time for immediate and delayed rework
, Article IIE Annual Conference and Expo 2007 - Industrial Engineering's Critical Role in a Flat World, Nashville, TN, 19 May 2007 through 23 May 2007 ; 2007 , Pages 1666-1671 ; Haji, R ; Ghayoor, Z ; Sharif University of Technology
2007
Abstract
This paper considers economic batch quantity (EBQ) in a single machine system in which defective items are produced and are all reworked in the same cycle. In the literature of inventory control, when the rework is done in the same cycle, the setup times are not considered; the rework process starts immediately after each production run, and the waiting of defectives for rework is ignored. Considering these points we assume non-zero setup times for rework, delayed rework in the same cycle, and the cost of waiting, to obtain the EBQ for two different cases
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...
Computer simulation of turbocharged aftercooled gasoline engine
, Article 8th Biennial ASME Conference on Engineering Systems Design and Analysis, ESDA2006, Torino, 4 July 2006 through 7 July 2006 ; Volume 2006 , 2006 ; 0791837793 (ISBN); 9780791837795 (ISBN) ; Hajilouy Benisi, A ; Mozafari, A. A ; Sharif University of Technology
American Society of Mechanical Engineers
2006
Abstract
Turbocharging of gasoline engines has been improved less than diesel engines due to some difficulties, especially knock phenomena. They require wider air flow range and faster response too. A computer code is developed to simulate turbocharged gasoline engine behavior. A three zone combustion model is employed. Different performance curves at speed and equivalence ratio ranges are prepared. By this code naturally aspirated and turbocharged behavior are compared. A turbocharged aftercooled engine has been studied in various cases to complete the investigation. Some aftercooler effects are described experimentally. Modeling and experimental results are compared providing valuable achievements....
Performance evaluation of mobile ad hoc networks in the presence of energy-based selfishness
, Article 2006 3rd International Conference on Broadband Communications, Networks and Systems, BROADNETS 2006, San Jose, CA, 1 October 2006 through 5 October 2006 ; 2006 ; 1424404258 (ISBN); 9781424404254 (ISBN) ; Movaghar, A ; Sharif University of Technology
2006
Abstract
Cooperation of nodes for routing and packet forwarding is inevitable in a mobile ad hoc network. Selfishness in such networks is a significant challenge and can cause network performance to noticeably degrade. In this paper, we propose some new selfishness models elicited from psychological behavior of human beings. We also evaluate performance of MANET in the presence of different percentages of selfish nodes that act based on our selfishness models. Results show that energy-based selfishness is a serious problem that could affect performance depends on mobility of nodes, density of network, and time of simulation. This kind of selfishness needs a comprehensive mechanism to cope with and we...
Co-flow fluidic thrust vectoring requirements for longitudinal and lateral trim purposes
, Article AIAA/ASME/SAE/ASEE 42nd Joint Propulsion Conference, Sacramento, CA, 9 July 2006 through 12 July 2006 ; Volume 8 , 2006 , Pages 6283-6292 ; 1563478188 (ISBN); 9781563478185 (ISBN) ; Banazadeh, A ; Sharif University of Technology
2006
Abstract
The feasibility of using fluidic thrust-vectoring system, as a control technique for the longitudinal and lateral trim purpose was investigated in this study. For this purpose, integration of a Co-flow method into the propulsion unit of a conceptual aerial vehicle was assumed. The focus of the research presented was to estimate the required thrust vector angle in order to trim the aerial vehicle in different flight phases. Since the fluidic thrust vectoring requires secondary air flow to deflect the engine exhaust gas, this research also provides an analytical toolset for preliminary sizing of a suitable secondary air supply. It was found that thrust vectoring could be an effective mean of...
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
A data recomputation approach for reliability improvement of scratchpad memory in embedded systems
, Article Proceedings - IEEE International Symposium on Defect and Fault Tolerance in VLSI Systems ; 2014 , pp. 228-233 ; Farbeh, H ; Monazzah, A. M. H ; Miremadi, S. G ; Sharif University of Technology
Abstract
Scratchpad memory (SPM) is extensively used as the on-chip memory in modern embedded processors alongside of the cache memory or as its alternative. Soft errors in SPM are one of the major contributors to system failures, due to ever-increasing susceptibility of SPM cells to energetic particle strikes. Since a large fraction of soft errors occurs in the shape of Multiple-Bit Upsets (MBUs), traditional memory protection techniques, i.e., Error Correcting Code (ECCs), are not affordable for SPM protection; mainly because of their limited error coverage and/or their high overheads. This paper proposes a novel algorithm that efficiently protects SPM with high error correction capability and...
Real-time hybrid switching control of automotive cold start hydrocarbon emission
, Article Journal of Dynamic Systems, Measurement and Control, Transactions of the ASME ; Vol. 136, issue. 4 , January , 2014 ; Shahbakhti, M ; Hedrick, J. K ; Sharif University of Technology
Abstract
Reduction of cold start hydrocarbon (HC) emissions requires a proper compromise between low engine-out HC emission and fast light-off of the three way catalytic converter (TWC). In this paper, a hybrid switching system is designed and optimized for reducing HC emissions of a mid-sized passenger car during the cold start phase of FTP-75 (Federal Test Procedure). This hybrid system has the benefit of increasing TWC temperature during the early stages of the driving cycle by switching between different operational modes. The switching times are optimized to reduce the cumulative tailpipe HC of an experimentally validated automotive emission model. The designed hybrid system is tested in...
Using genetic algorithm to identify soft-error derating blocks of an application program
, Article Proceedings - 15th Euromicro Conference on Digital System Design, DSD 2012, 5 September 2012 through 8 September 2012 ; September , 2012 , Pages 359-367 ; 9780769547985 (ISBN) ; Rahmani, A. M ; Mansoor, A ; Miremadi, S. G ; Sharif University of Technology
2012
Abstract
Soft-errors are increasingly considered as a major cause for computer system failures. Software techniques are used as cost-effective and flexible techniques to tolerate soft-errors but the introduced overhead is not acceptable in some safety-critical real-time systems. The identification of the program blocks and protecting only vulnerable blocks against soft-errors reduces the performance overhead. In this paper, we present a genetic algorithm to identify the vulnerable program blocks as well as the derating program blocks against soft-errors. Then, only vulnerable blocks are protected by some software-based soft-error tolerance techniques to achieve a lower performance and space overhead....
Systems engineering of Omid, the first domestic satellite of the I.R. of Iran
, Article Systems Engineering ; Volume 15, Issue 3 , May , 2012 , Pages 307-320 ; 10981241 (ISSN) ; Pourtakdoust, S. H ; Abolghasemi, M ; Tivay, M ; Sharif University of Technology
2012
Abstract
In keeping with the continuing effort toward the development of a domestic space research and development program in recent years, the Omid National Satellite (ONS) is the first domestically manufactured satellite from the Islamic Republic of Iran. As a technology demonstration, it was launched and utilized successfully in February 2009. Despite the simple mission of the ONS, because it was the first full-scale successful space deployment experience for the country, the domestic manufacturing capabilities for satellite and launch technologies were boosted. More importantly, the country's domestic platform for future space projects was established. Considering the important role of systems...
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...
Performance investigation of a four stroke diesel engine, using water-based ferrofluid as an additive
, Article ASME 2011 International Mechanical Engineering Congress and Exposition, IMECE 2011, 11 November 2011 through 17 November 2011 ; Volume 4, Issue PARTS A AND B , November , 2011 , Pages 1339-1343 ; 9780791854907 (ISBN) ; Jahani, N ; Shafii, M. B ; ASME ; Sharif University of Technology
Abstract
In this experimental study, a four stroke diesel engine was conducted to investigate the effect of adding water-based ferrofluid to diesel fuel on engine performance. To our knowledge, Magnetic nanoparticles had not been used before. To this end, emulsified diesel fuels of 0, 0.4, and 0.8 water-based ferrofluid/Diesel ratios by volume were used as fuel. The ferrofluid used in this study was a handmade water-based ferrofluid prepared by the authors. The results show that adding water-based ferrofluid to diesel fuel has a perceptible effect on engine performance, increasing the brake thermal efficiency relatively up to 12%, and decreasing the brake specific fuel consumption relatively up to...