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Semi-optimal co-ordinated manoeuvres for aircraft conflict resolution
, Article Aeronautical Journal ; Volume 109, Issue 1097 , 2005 , Pages 313-323 ; 00019240 (ISSN) ; Malaek, M. B ; Sharif University of Technology
Royal Aeronautical Society
2005
Abstract
In this manuscript, a new concept of 2D-semi-optimal-circular-3-arced-path manoeuvres with constant speed for multiple aircraft cooperative conflict resolution is presented. This type of manoeuvres is based on appropriate commands to heading, speed and manoeuvreing time. According to aircraft turning dynamics, each aircraft manoeuvre is composed of three tangent circular arcs. The optimality of manoeuvres is based on the minimisation of weighted sum of kinetic energy for aircraft two-legged manoeuvres. In comparison, aircraft with lower weight factors bear more responsibility to resolve the conflicts. The effectiveness of the proposed algorithm for real time conflict resolution is...
Efficient Management of River Water Quality Based on Pollution Trading Approach
, Ph.D. Dissertation Sharif University of Technology ; Shamsai, Abolfazl (Supervisor)
Abstract
“Sustainable development” is a frequently used phrase, but the idiom has been experienced little since it was coined by the Brundtland, due to its intrinsic complications. The issue is going to compromise two key components; economy and ecology. One of the solutions based on concept of sustainable development that has been proposed for maintaining water quality at acceptable levels is to cap pollutant emissions at a sustainable level, then establish an economic market in which the right to discharge pollutants is traded according to market supply and demand mechanisms. Water quality trading or pollution trading is one such kind of market-based program that has also been described using names...
The Application of Deep Learning in House Price Prediction
, M.Sc. Thesis Sharif University of Technology ; Rafiee, Majid (Supervisor) ; Shavandi, Hassan (Co-Supervisor)
Abstract
Today, estimating housing prices is very important in different societies. The reason for this growing importance can be considered the role of housing in the economic decisions and policies of any society. This estimate is made using the quantitative and qualitative characteristics of each housing and in different ways. In the past, housing prices were estimated using traditional models, but in the present century, due to easier and more access to the Internet and the development of organizations and businesses in this context, which produces a huge amount of data, the use of traditional models for this purpose is not possible. Therefore, today the use of other methods such as machine...
An application of quality function deployment method in engineering materials selection
, Article Materials and Design ; Vol. 55, issue , 2014 , p. 912-920 ; Abedian, A ; Milani, A. S ; Sharif University of Technology
Abstract
In transition from concept design to detail design, designers and engineers need to find specific materials to optimize performance of the systems. The large number of materials and the wide range of manufacturing processes cause engineers always to seek new materials selection methods. In this research work a new method so called QFD method, which employs materials indices, is introduced. The method enjoys a combination of Ashby's materials selection concepts with the Quality Function Deployment (QFD) tool. The QFD method, which is modified here to fit the materials selection field, provides the designer with the required weighting factors for the material indices. Incorporation of House of...
An energy-efficient leader selection algorithm for cooperative mobile clouds
, Article IFIP Wireless Days, Valencia ; November , 2013 , Page(s): 1 - 4 ; 21569711 (ISSN) ; 9781479905423 (ISBN) ; Salehi, M. J ; Khalaj, B. H ; Katz, M ; Sharif University of Technology
IEEE Computer Society
2013
Abstract
In this paper, we propose and study a context-aware leader selection algorithm within the concept of mobile clouds. We deploy a dedicated Cooperative Control Server (CCS) to assist and manage the process of leader selection more efficiently. The proposed algorithm collects data regarding instantaneous conditions of Mobile Terminals (MTs) and their radio environment; and then computes and assigns a rank to each MT. The ranks calculated based on a combination of different context-related parameters and corresponding weighting factors, allow selecting the leader. Furthermore, the energy efficiency and stability of the selected leaders is investigated for different parameter values through...
Application of artificial neural networks to prediction of chemical composition of electrodeposited Ni-Mo thin films
, Article ECS Transactions ; Volume 50, Issue 52 , Oct , 2012 , Pages 63-71 ; 19385862 (ISSN) ; Rouhaghdam, A. S ; Aliofkhazraie, M ; Shahrabi, T ; Ashrafi, A ; Seddighian, A ; Sharif University of Technology
2012
Abstract
Present research represents the application of artificial neural networks to predict the chemical composition of electrodeposited Ni-Mo thin films. Artificial neural networks commonly are utilized as a prediction tools so that these networks could approximately find kind of logic relationships between inputs and target; they fitted appropriate coefficient and weighting factors to the inputs which are proportional to their importance. In order to evaluate the model developed, experimental results were compared with the predicted ones. However, more data are required to train more reliable prediction models, presents study revealed an acceptable error less than 1% between predicted values and...
A novel method for materials selection in mechanical design: Combination of non-linear normalization and a modified digital logic method
, Article Materials and Design ; Volume 28, Issue 1 , 2007 , Pages 8-15 ; 02613069 (ISSN) ; Mahmudi, H ; Abedian, A ; Mahmudi, R ; Sharif University of Technology
Elsevier Ltd
2007
Abstract
In this investigation, a novel numerical method is proposed for materials selection. This method is based on the well known weighting factor approach while combining non-linear normalization with a modified digital logic method. The proposed mathematical functions and their applicability to the materials selection process is verified by examining two case studies in mechanical design and comparing the results with those obtained from the classical weighted property method. It is concluded that the new approach is capable of providing more reasonable selections as opposed to those obtained from the existing method. © 2005 Elsevier Ltd. All rights reserved
Materials selection for applications in space environment considering outgassing phenomenon
, Article Advances in Space Research ; Volume 45, Issue 6 , 2010 , Pages 741-749 ; 02731177 (ISSN) ; Abedian, A ; Sharif University of Technology
Abstract
Application of the existing materials selection methods is not much popular in space environment. This is in spite of involvement of the selection process in this field with a wide range of influential factors (e.g. conventional mechanical properties and over 21 space environmental effects). In this paper an introductory road map for employing systematic materials selection methods in the field by engaging the selection process with mechanical properties and only one of the space environmental factors is presented. Here, selected case studies, which are involved with outgassing phenomenon of materials in vacuum condition, highlight the incapability of some of the methods in dealing with such...
Utilization of analytical hierarchy process in contingency ranking
, Article 2009 IEEE/PES Power Systems Conference and Exposition, PSCE 2009, Seattle, WA, 15 March 2009 through 18 March 2009 ; 2009 ; 9781424438112 (ISBN) ; Ehsan, M ; Ghofrani Jahromi, Z ; Masjed Jamei, M ; Sharif University of Technology
2009
Abstract
Contingency screening and ranking is one of the most important issues for security assessment in the field of power system operation. The objective of contingency screening and ranking is to quickly and accurately select a short list of critical contingencies from a large list of potential contingencies and rank them according to their severity. Then suitable preventive control actions can be implemented considering contingencies that are likely to affect the power system performance. In this paper a novel approach is presented for contingency ranking based on static security assessment (SSA). This method uses weighted performance index with the application of Analytical Hierarchy Process...
Measure the Project Progress with Standard Weight Factors and Calculate the Project Performance
, M.Sc. Thesis Sharif University of Technology ; Shadrokh, Shahram (Supervisor)
Abstract
One of the methods that we used today to manage project are calculating project progress. By which we can calculate the actual progress of project by comparison the actual plan with the schedule plan. If the actual progress,measured with less error, then the control of project done with high accuracy.Project progress are calculated in control account. For this reason, if the number of control account increased, the accuracy of the calculation increased and on the other hand whatever this control account increase the amount of time used to collect information also increases. In this study, we are looking to create mathematical model that in addition increases the accuracy of measurement,also...
Transmission loss allocation using normalized loss weight factors
, Article 3rd International Conference on Deregulation and Restructuring and Power Technologies, DRPT 2008, Nanjing, 6 April 2008 through 9 April 2008 ; 2008 , Pages 431-435 ; 9787900714138 (ISBN) ; Ehsan, M ; Sharif University of Technology
2008
Abstract
One of the major problems in liberalized power markets is loss allocation. In this paper, a new method for allocating transmission losses to pool market participants is proposed. The proposed method is fundamentally based on Bialek's "Tracing the flow of electricity" method. The losses is allocated to market participants using the loss weight factors (LWFs) which are obtained from the square current magnitude and Z-bus matrix. The LWF method is based on a solved load flow and strongly emphasizes on current magnitude while considers network topology. The method has been implemented and tested on several networks and one sample summarized in the paper. The results show that the method has an...
Optimizing the geometry of a half-toroidal CVT
, Article Powertrain and Fluid Systems Conference and Exhibition, San Antonio, TX, 24 October 2005 through 27 October 2005 ; 2005 ; 01487191 (ISSN) ; Zohoor, H ; Sharif University of Technology
SAE International
2005
Abstract
In this research a model is developed which calculates the torque transmission efficiency of a half-toroidal CVT as a function of variator geometry, gear ratio and input torque. The different criteria which are considered to be important in a half toroidal CVT performance are torque transmission efficiency, variator weight, roller fatigue life and bearing torque loss. Variation of geometrical characteristics such as roller curvature, number of power rollers, aspect ratio and half cone angle affect these criteria in different ways. Therefore, in order to find the optimal quantity for each geometrical parameter an optimization problem should be developed. The objective function of this...
Materials selection for electronic enclosures in space environment considering electromagnetic interference effect
, Article Advances in Space Research ; Volume 49, Issue 3 , February , 2012 , Pages 586-593 ; 02731177 (ISSN) ; Abedian, A ; Sharif University of Technology
2012
Abstract
Using low power electronic devices for space applications to reduce the mass and energy consumption has lead to electromagnetic interference (EMI) problem. Electronic enclosures are used to shield electronic devices against EMI. In the past, electromagnetic shielding has been mainly the only criteria considered in electronic enclosure design. However, there are several structural and thermal requirements for selection of shielding materials which should also be taken into account. In this research work, three quantitative materials selection methods, i.e. Digital Logic (DL), Modified Digital Logic (MDL), and Z-transformation, are employed to select the best material from among a list of...
Environmental parametric cost model in oil and gas EPC contracts
, Article Sustainability (Switzerland) ; Volume 10, Issue 1 , 2018 ; 20711050 (ISSN) ; Toutounchian, S ; Dana, T ; Abedi, Z ; Toutounchian, S ; Sharif University of Technology
MDPI AG
2018
Abstract
This study aims at identifying the parameters that govern the environmental costs in oil and gas projects. An initial conceptual model was proposed. Next, the costs of environmental management work packages were estimated, separately and were applied in project control tools (WBS/CBS). Then, an environmental parametric cost model was designed to determine the environmental costs and relevant weighting factors. The suggested model can be considered as an innovative approach to designate the environmental indicators in oil and gas projects. The validity of variables was investigated based on Delphi method. The results indicated that the project environmental management's weighting factor is...
Transmission loss allocation using normalized loss weight factors
, Article 10th International Conference on Probabilistic Methods Applied to Power Systems, PMAPS 2008, Rincon, 25 May 2008 through 29 May 2008 ; 2008 , Pages 224-228 ; 9781934325216 (ISBN) ; Ehsan, M ; Sharif University of Technology
2008
Abstract
One of the major problems in liberalized power markets is loss allocation. In this paper, a new method for allocating transmission losses to pool market participants is proposed. The proposed method is fundamentally based on Bialek's "Tracing the flow of electricity" method. The losses is allocated to market participants using the loss weight factors (LWFs) which are obtained from the square current magnitude and Z-bus matrix. The LWF method is based on a solved load flow and strongly emphasizes on current magnitude while considers network topology. The method has been implemented and tested on several networks and one sample summarized in the paper. The results show that the method has an...
Multiple interactive pollutants in water quality trading
, Article Environmental Management ; Volume 42, Issue 4 , 2008 , Pages 620-646 ; 0364152X (ISSN) ; Lence, B. J ; Shamsai, A ; Sharif University of Technology
2008
Abstract
Efficient environmental management calls for the consideration of multiple pollutants, for which two main types of transferable discharge permit (TDP) program have been described: separate permits that manage each pollutant individually in separate markets, with each permit based on the quantity of the pollutant or its environmental effects, and weighted-sum permits that aggregate several pollutants as a single commodity to be traded in a single market. In this paper, we perform a mathematical analysis of TDP programs for multiple pollutants that jointly affect the environment (i.e., interactive pollutants) and demonstrate the practicality of this approach for cost-efficient maintenance of...