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process-engineering
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An extended model of design process of lean production systems by means of process variables
, Article Robotics and Computer-Integrated Manufacturing ; Volume 22, Issue 1 , 2006 , Pages 1-16 ; 07365845 (ISSN) ; Jamshidnezhad, B ; Sharif University of Technology
2006
Abstract
In this paper, we present an axiomatic modeling of lean production system design, using process variables (PVs). So far, we had developed a model for conceptual design of lean production systems by means of FR-DP relationships, the key characteristics of axiomatic design (AD) methodology, appeared in the proceedings of Second International Conference of Axiomatic Design. Albeit the model in question was thorough enough to be applied in various cases, its embedded abstract principles hamper straightforward applications and the required resources, tools, and techniques are not clarified. In AD terms, it lacks PVs created by mapping the design parameters (DPs) to the process domain to clarify...
Time decomposition in batch process integration
, Article Chemical Engineering and Processing: Process Intensification ; Volume 45, Issue 1 , 2006 , Pages 14-21 ; 02552701 (ISSN) ; Amidpour, M ; Rashtchian, D ; Sharif University of Technology
2006
Abstract
In this work, the concept of problem table decomposition for the thermal integration of continuous processes is extended to batch processes. The approach is based on a combination of time intervals using pinch analysis tools and energy storage system design. Pinch analysis improves energy efficiency for batch processes and it may increase the productivity of a revised plant. Operational and economical constraints may cause some limitation; therefore, in this approach process constraints and flexibilities are carefully considered by defining individual time and heat intervals. The approach is demonstrated on a case study. © 2005 Elsevier B.V. All rights reserved
Axiomatic design of step down DC/DC converter
, Article 2008 IEEE International Conference on Industrial Technology, IEEE ICIT 2008, Chengdu, 21 April 2008 through 24 April 2008 ; 2008 ; 9781424417063 (ISBN) ; Haddadi, A ; Khaligh, A ; Sharif University of Technology
2008
Abstract
In this paper, the axiomatic design is introduced for designing the power electronic converters. The main idea of axiomatic design is to introduce variables affecting the desired performances of the system most independently possible. The design process is presented for a Buck converter. ©2008 IEEE
An efficient multi-band spectral subtraction method for robust speech recognition
, Article 2007 9th International Symposium on Signal Processing and its Applications, ISSPA 2007, Sharjah, 12 February 2007 through 15 February 2007 ; 2007 ; 1424407796 (ISBN); 9781424407798 (ISBN) ; Sameti, H ; Babaali, B ; Manzuri Shalmani, M. T ; Sharif University of Technology
2007
Abstract
In this paper we present a novel approach for adjusting a multi band spectral subtraction filter coefficients based on speech recognition system results. Currently most speech enhancement techniques are designed according to various waveform level criteria such as maximizing SNR or minimizing signal error. However improvement in these criteria does not necessarily result in increasing speech recognition performance. Only if these methods generate sequence of features that maximize or increase the likelihood of the correct transcription relative to other incorrect competing hypotheses, speech recognition performance will increase. Here we use an utterance with a known transcription and...
Economic production quantity with accumulated rework
, Article 36th International Conference on Computers and Industrial Engineering, ICC and IE 2006, Taipei, 20 June 2006 through 23 June 2006 ; 2006 , Pages 4196-4203 ; Tavakol, A. R ; Haji, B ; Sharif University of Technology
2006
Abstract
This paper deals with the issue of economic batch quantity (EBQ) in a single machine system in which defective items are produced in each cycle of production. The defective items produced in the first N cycles are accumulated at the end of the Nth cycle and are all reworked in a separate cycle called the rework cycle which has the same length as the other cycles and begins just at the end of the Nth cycle. At the end of the rework cycle the whole process will start all over again. For this system, assuming no shortages are permitted we obtain the economic batch quantity which minimizes the total cost
Online exams and the COVID-19 pandemic: a hybrid modified FMEA, QFD, and k-means approach to enhance fairness
, Article SN Applied Sciences ; Volume 3, Issue 10 , 2021 ; 25233971 (ISSN) ; Shabani, S ; Sharif University of Technology
Springer Nature
2021
Abstract
COVID-19 pandemic caused an increasing demand for online academic classes, which led to the demand for effective online exams with regards to limitations on time and resources. Consequently, holding online exams with sufficient reliability and effectiveness became one of the most critical and challenging subjects in higher education. Therefore, it is essential to have a preventive algorithm to allocate time and financial resources effectively. In the present study, a fair test with sufficient validity is first defined, and then by analogy with an engineering product, the design process is implemented on it. For this purpose, a hybrid method based on FMEA, which is a preventive method to...
Design and Optimization of Helium Recovery Process from Natural Gas
, M.Sc. Thesis Sharif University of Technology ; Afshin, Hossein (Supervisor) ; Farhanieh, Bijan (Co-Supervisor)
Abstract
Helium is a valuable substance that is widely used in industry and medicine because of its unique properties. Due to the increasing demand for helium in the global market, several helium extraction units have been launched in the world in recent years; Nevertheless, there is still a significant gap between projected global helium production capacity and demand. Today, natural gas is known as the main source of helium on the earth. The method of industrial extraction of helium from natural gas is cryogenic. Due to the low temperature of this process, relatively high power consumption is used to extract helium from natural gas. Therefore, the optimization of this process is of great...
Design and Optimization of Helium Extraction and Liquefaction Cycle from Natural Gas by Direct Method
, Ph.D. Dissertation Sharif University of Technology ; Afshin, Hossein (Supervisor)
Abstract
Helium is known as a strategic material due to its unique properties and applications in the development of advanced industries. Currently, natural gas is the only source from which helium can be produced economically. The United States, Qatar, Algeria, and Russia have the largest share of helium production, respectively. In this research, the process of helium extraction from natural gas and its liquefaction, independent of LNG production based on helium in South Pars gas of Iran, which is the largest helium reservoir in the world, were designed and simulated.In the helium liquefaction section, the speed and accuracy of the process simulation were improved by developing a home code based on...
INFELT STEP: An integrated and interoperable platform for collaborative CAD/CAPP/CAM/CNC machining systems based on STEP standard
, Article International Journal of Computer Integrated Manufacturing ; Volume 23, Issue 12 , 2010 , Pages 1095-1117 ; 0951192X (ISSN) ; Houshmand, M ; Sharif University of Technology
Abstract
Integrated product development is comprised of CAD, process planning and CNC code generation based on an integrated data structure. To make various CAD/CAM software solutions with different internal product data structures interoperable, it is necessary to realise reliable and robust information exchange capability in a manufacturing environment. To enable interoperability amongst integrated product development processes, management of collaboration of diverse CAD/CAM software packages is of outmost importance. In this article, the fundamental requirements for achieving interoperability and collaboration management in an integrated, enterprise-wide, product development process environment...
Evaluating the capability of distribution networks to maintain power quality and voltage level, case study: alborz electric power distribution company
, Article IET Generation, Transmission and Distribution ; Volume 12, Issue 16 , 2018 , Pages 3883-3891 ; 17518687 (ISSN) ; Rezaie, K ; Fotuhi Firuzabad, M ; Sharif University of Technology
Abstract
Distribution system operators that seek operational excellence are supposed to design and implement capable processes throughout their value stream and assess how well their real services match the design specifications. Process capability analysis is a critical stage in systematic and sophisticated quality engineering approaches such as six sigma, which are based on quantitative studies. The capability of a distribution network to maintain the power quality and voltage level within an acceptable range is one of the most important aspects of design and utilisation of electricity distribution network. Capability analysis has been successfully used in the previous studies to assess the quality...
Multivariate nonnormal process capability analysis
, Article International Journal of Advanced Manufacturing Technology ; Volume 44, Issue 7-8 , 2009 , Pages 757-765 ; 02683768 (ISSN) ; Abdollahian, M ; Zeephongsekul, P ; Abbasi, B ; Sharif University of Technology
2009
Abstract
There is a great deal of interest in the manufacturing industry for quantitative measures of process performance with multiple quality characteristics. Unfortunately, multivariate process capability indices that are currently employed, except for a handful of cases, depend intrinsically on the underlying data being normally distributed. In this paper, we propose a general multivariate capability index based on the Mahanalobis distance, which is very easy to use. We also approximate the distribution of these distances by the Burr XII distribution and then estimate its parameters using a simulated annealing search algorithm. Finally, we give an example, based on real manufacturing process...
Method engineering process patterns
, Article 2nd India Software Engineering Conference, ISEC 2009, Pune, 23 February 2009 through 26 February 2009 ; 2009 , Pages 143-144 ; 9781605584263 (ISBN) ; Ramsin, R ; Computer Society of India ; Sharif University of Technology
2009
Abstract
Method Engineering (ME) is based on the notion that no two software development projects are identical, and hence, the same development process is never executed twice. The need therefore arises for custom-built software development methodologies that are tailored to fit the specific project situation at hand, thus giving rise to the various Situational Method Engineering (SME) approaches currently in use. A process pattern is a description of a recurring development process fragment that can be used as a building block for engineering development processes. Software development process patterns are extensively used in SME, mainly as process components assembled together to form bespoke...
Automatic design of conventional distillation column sequence by genetic algorithm
, Article Canadian Journal of Chemical Engineering ; Volume 87, Issue 3 , 2009 , Pages 477-492 ; 00084034 (ISSN) ; Pourahmadi Laleh, A ; Svrcek, W. Y ; Sharif University of Technology
2009
Abstract
Synthesis of the optimum conventional (with non-sharp separations) distillation column sequence (DCS) is a challenging problem, in the field of chemical process design and optimization, due to its huge search space and combinatorial nature. In this paper, a novel procedure for the synthesis of optimum Conventional Distillation Column Sequence is proposed. The proposed method is based on evolutionary algorithms. The main criterion used to screen alternative DCS's is the Total Annual Cost (TAC). In order to estimate the TAC of each DCS alternative all columns that exist in the DCS are designed using short-cut methods. The performance of the proposed method and other alternatives are compared...
Application of scheduling models for utility management of process plants and its extension to DG networks
, Article 2008 1st International Conference on Infrastructure Systems and Services: Building Networks for a Brighter Future, INFRA 2008, Rotterdam, 10 November 2008 through 12 November 2008 ; 2008 ; 9781424468874 (ISBN) ; Pishvaie, M. R ; Sharif University of Technology
2008
Abstract
Scheduling models are one of the main parts of computer-aided process design research in recent years. One of the novel applications of scheduling models is their usage for in-site utility management of a process plant. It is very common for huge process plants to provide their utility by themselves; therefore, they shall make decision on utility supply and demand simultaneously. This approach can be extended to other similar systems such as distributed generation networks. In fact, it is possible to consider a DG unit as an autonomous system which is responsible for its energy (heat and power) supply and demand. Of course, for achieving its reliability and dispatchability goals, it would...
A novel GA-based High-Level Synthesis technique to enhance RT-level concurrent testing
, Article 14th IEEE International On-Line Testing Symposium, IOLTS 2008, Rhodes, 7 July 2008 through 9 July 2008 ; 2008 , Pages 173-174 ; 9780769532646 (ISBN) ; Aminzadeh, S ; Safari, S ; Navabi, Z ; Sharif University of Technology
2008
Abstract
This paper presents an efficient High-Level Synthesis (HLS) approach to improve RT-Level concurrent testing. The proposed method used for both fault detection and fault location. At first the available resources are used in their dead intervals to test active resources for fault detection, and then some changes are applied to the RT-Level controller to locate the faults. The fault detection step is based on a genetic algorithm (GA) search technique. This genetic algorithm is applied to the design after high level synthesis process to explore the test map. The proposed method has been evaluated based on dependability enhancement and area/latency overhead imposed to different benchmarks after...
Unsteady three dimensional aerodynamic load prediction using neural networks
, Article 2007 International Joint Conference on Neural Networks, IJCNN 2007, Orlando, FL, 12 August 2007 through 17 August 2007 ; 2007 , Pages 1995-1999 ; 10987576 (ISSN) ; 142441380X (ISBN); 9781424413805 (ISBN) ; Ghorbanian, K ; Gholamrezaei, M ; Amiralaei, M. R ; Sharif University of Technology
2007
Abstract
The focus of the current research is to develop an intelligent design process that uses existing data as a tool for the designers, one that fully utilizes the ability of the computer to interpolate and extrapolate the scattered data. Surface pressure measurements were conducted for a pitch oscillation wing in a subsonic closed circuit wind tunnel. Experimental results have been used to train a multilayer perceptron network. This work indicates that neural networks can reliably predict aerodynamic coefficients and forecast the effects of reduced frequencies on the wind turbine blade performance. ©2007 IEEE
Study the failure of casted copper anode: The formation of bumps defects on the surface of the anode during casting
, Article Engineering Failure Analysis ; Volume 138 , 2022 ; 13506307 (ISSN) ; Reza Khayati, G ; Javad Khorasani, S. M ; Assadat Yaghubi, N ; Sharif University of Technology
Elsevier Ltd
2022
Abstract
Copper anode (∼98%) is widely used to produce the cathode (99.995 wt%) in electrorefining process. These anodes sometimes become problematic from the production line due to the presence of bumps/holes on their surface. To find the reason of this defect, chemical composition of the three casted anodes was determined by the quantmeter analysis. Also, the microscopic and phase analysis were done by FESEM, EDS, XRD, and XRF for three types of anodes bump. The chemical analysis of anodes confirmed a high level of sulfur and oxygen, which have a key role in the formation of bumps. The results confirmed the presence of impurities including Cu2S, BaSO4, CaCO3 and MgCO3, which cause the formation of...
Intelligent flight-data-recorders; a step toward a new generation of learning aircraft
, Article 8th International Conference on Control, Decision and Information Technologies, CoDIT 2022, 17 May 2022 through 20 May 2022 ; 2022 , Pages 1545-1549 ; 9781665496070 (ISBN) ; Alipour, E ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
To understand how aerial accidents occur, the installation of flight data recorders (FDR) and cockpit voice recorders (CVR) have become mandatory by law. However, such devices play a passive role and are used once an accident has occurred. Recent advances in machine learning techniques and their application in solving engineering problems are the keys to creating a more active role for both FDR as well as CVR. Here, we investigate a new approach to bringing intelligence to an FDR (called I-FDR). Through a continuous data-mining process, an I-FDR could bring better situational awareness to the flight crew. An I-FDR, similar to the FDR, records all pertinent flying parameters. In addition,...
Definition of a Set of Process Patterns and a Generic Meta-Model for Component-Based Development Methodologies
, M.Sc. Thesis Sharif University of Technology ; Ramsin, Raman (Supervisor)
Abstract
Although Component-Based Development (CBD) is not a novel approach, it is still extensively used for building various types of software systems, and is expected to remain popular for the foreseeable future. There exist several software development methodologies that support the construction of component-based systems, and the domain has matured over the years. When viewed collectively, CBD methodologies have indeed addressed all the relevant issues; however, none of the methodologies covers all the aspects of component-based software development. A general methodology can resolve this through addressing the deficiencies while being customizable according to the specifics of the project...
Towards tool support for situational engineering of agile methodologies
, Article Proceedings - Asia-Pacific Software Engineering Conference, APSEC, 30 November 2010 through 3 December 2010, Sydney, NSW ; 2010 , Pages 326-335 ; 15301362 (ISSN) ; 9780769542669 (ISBN) ; Hasani Sadi, M ; Ramsin, R ; Sharif University of Technology
2010
Abstract
Various agile software development methodologies, practices, and techniques have been proposed in the last decade; some present novel ideas, while many are simply made up of tasks and techniques borrowed from prominent agile methodologies. Each of these methodologies prescribes a set of practices and techniques which are deemed appropriate for application in a specific context. However, there exists no single method which fits all project situations. This has resulted in the advent of Situational Method Engineering (SME) approaches, which are used for developing software methodologies that are tailored to fit the specific circumstances of the project situation at hand. Since tool support has...