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Identification and Modeling Of Factors Affecting The Waiting Time of Pedestrians to Cross at Signalized Intersections
, M.Sc. Thesis Sharif University of Technology ; Nasiri, Habibollah (Supervisor)
Abstract
Studies show that Pedestrians are at fault in 59% of the vehicle-pedestrian accidents. The traffic crash statistics show the importance of understanding factors of pedestrian errors. If pedestrians terminate their waiting behavior during the red light period and cross the street, they would put themselves in danger. Pedestrians’ red-light violation is a type of highly dangerous behavior occurring at intersections. A total of 1130 pedestrians approaching the intersections during red light periods were observed from the videotapes data collected at 6 intersections in Tehran, Iran. Pedestrian crossing behaviors are classified into immediate crossing behavior and waiting behavior. A logit model...
Probabilistic Safety Assessment of A UF6 Production Process
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor)
Abstract
Identification of different hazards in a UF6 production process, and evaluation of the risk originated from these hazards is the main objective of this project. A number of hazards are present in a typical UF6 production process, such as leakage of chemical gases like HF and F2 and also radioactive UF6 gas release. In order to evaluate risk due to these hazards, probabilistic approach has been used. Due to lack of probabilistic safety criteria (PSC) for chemical releases, only for UF6 gas release risk assessment has been done. As a first step in PSA of this process eight groups of initiating events have been identified using HAZOP study, and for each initiating event, event tree analysis...
A Motivational Model for Building Virtual Auction
, M.Sc. Thesis Sharif University of Technology ; Amini Lari, Mansour (Supervisor) ; Beirjandi, Heshmat ($item.subfieldsMap.e)
Abstract
Construction is a large industry in Iran, it engages in a wide range of products. The raw materials which are used in making a building are fairly standard items: iron, cement, glass, and so on. Because the technologies for making a building are well-known, contractor can solicit bids from variety suppliers for raw materials without worrying about the possible disclosure of trade secrets. Unfortunately bidding processing in Iran becomes very slow and inefficient. Each transaction required to request the relevant telephone number to supplier that might be interested in bidding on the item, it would often take purchasing personnel more than one week to gather the information, send it to...
Analysis of high risk occupational accidents in construction industry using data-mining methods
, Article Iran Occupational Health ; Vol. 11, Issue 4 , 2014 , pp. 31-43 ; Ardeshir, A ; Aghaie, S. E ; Sharif University of Technology
Abstract
Background and aims: Among different types of occupational accidents in the construction industry, falls and falling objects accidents (group I) account for 44% of construction accidents. Hit by vehicle, electric shock, collapse in the excavation and fire or explosion accidents (group II), while are only 7% frequent, make up about 26% of all fatalities and total disabling accidents. The aim of this study is to investigate these two groups of accidents and to discuss the obtained results in order to identify the potential hazards of construction industry. Methods: Data mining methods are employed to analyze data in this research. Hence, 21864 data records which were provided by Social...
Risk measures for minimization of earthquake costs
, Article Safety, Reliability, Risk and Life-Cycle Performance of Structures and Infrastructures - Proceedings of the 11th International Conference on Structural Safety and Reliability, ICOSSAR 2013 ; 2013 , Pages 2619-2626 ; 9781138000865 (ISBN) ; Allahdadian, S ; Mahsuli, M ; Sharif University of Technology
2013
Abstract
The total cost of earthquakes is in this paper modeled as a continuous random variable that includes the cost of damage and the cost of construction to prevent damage. Realizations of this variable are obtained by evaluating an array of probabilistic models that take many basic random variables as input. Consequently, analyses can be conducted to determine the mean cost, as well as cost exceedance probabilities and other measures of seismic risk. Such results are employed to address the underlying decision problem, namely to minimize the total cost of earthquakes when that cost is a continuous random variable. Applicable decision theories are outlined and several risk measures are...
Probabilistic safety assessment of a UF 6 production process
, Article Advances in Safety, Reliability and Risk Management - Proceedings of the European Safety and Reliability Conference, ESREL 2011 ; 2012 , Pages 1384-1389 ; 9780415683791 (ISBN) ; Sharif University of Technology
2012
Abstract
Application of Probabilistic Safety Assessment (PSA) to a Uranium hexafluoride (UF 6) production process is presented in this paper. The process is constituted from three main units: UF 4 conversion to UF 6, condensation of produced UF 6 gas and tail gas treatment. Radioactive gas is present in all parts of the process and occurrence of high pressure or high temperature in the process equipments may lead to radioactive release to workplace and environment. The work is mainly based on PSA experience in nuclear power plants. Accordingly for the process, eight group of Initiating Events (IE) that lead to UF 6 gas release have been identified using HAZOP study. For each IE, based on related...
Experimental evaluation of Master/Checker architecture using power supply- and software-based fault injection
, Article Proceedings - 10th IEEE International On-Line Testing Symposium, IOLTS 2004, Madeira Island, 12 July 2004 through 14 July 2004 ; 2004 , Pages 239-244 ; 0769521800 (ISBN); 9780769521800 (ISBN) ; Miremadi, S. G ; Mohandespour, M ; Sharif University of Technology
2004
Abstract
This paper presents an experimental evaluation of the effectiveness of the Master/Checker (M/C) architecture in a 32-bit Pentium® processor system using both power-supply disturbance (PSD) fault injection and software-implemented fault injection (SWIFI) methods. A total of 6000 faults were injected in the Master processor to measure the error detection coverage of the Checker processor. The results of the experiments with PSD fault injection show that the error detection coverage of the M/C architecture is about 66.13%, which is not quite effective. This low coverage depends on the high rate of Master processor hangs because of voltage fluctuation. The coverage increased to about 99.73% when...
Recovery of preload in bolted joint using shape memory alloy elements
, Article 2003 ASME Design Engineering Technical Conferences and Computers and Information in Engineering Conference, Chicago, IL, 2 September 2003 through 6 September 2003 ; Volume 5 C , 2003 , Pages 1843-1849 ; Inman, D. J ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME)
2003
Abstract
One of the main problems with a bolted joint is losing its preload. In this situation, it cannot provide the required clamping force needed to keep the joint members together or prevent fluid leakages. Although every effort is usually made at the design stage to prevent such failure, because of the numerous factors present in the problem, these efforts are not always successful. After loosening occurs, the joint should be retightened to regain its preload. However, there are circumstances where the joint is very important but it is not easily accessible and retightening cannot be done manually. The shape memory effect (SME) property can be used in such circumstances to produce the necessary...
Sensitivity of a real-time freeway crash prediction model to calibration optimality
, Article European Transport Research Review ; Volume 4, Issue 3 , September , 2012 , Pages 167-174 ; 18670717 (ISSN) ; Hellinga, B ; Sharif University of Technology
2012
Abstract
Background: Real-time crash prediction models are often structured as general log-linear categorical models which must be calibrated using an extensive database. However, there is no method to optimally select the number of categories and the values that define the boundaries between categories when representing continuous measures as categorical variables within the log-linear model. This raises the question of how important the calibration is to the safety impacts estimated when using the crash prediction model. In this paper, we examined the impact that the process used to calibrate the crash prediction model has on estimates of safety impacts of a variable speed limit system. Methods:...
Design of a hybrid controller for pressure swing adsorption processes
, Article IEEE Transactions on Control Systems Technology ; 2018 ; 10636536 (ISSN) ; Bozorgmehri Boozarjomehry, R ; Fatemi, S ; De Santis, E ; Di Benedetto, M. D ; Pola, G ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
The aim of this paper is to synthesize a hybrid controller for pressure swing adsorption (PSA) processes. Since the process is described by a set of partial differential algebraic equations, first a local reduced-order model (LROM) for the process is developed and is formalized as a hybrid system. A hybrid controller is designed for purity control of the process in the presence of external disturbances by determining the maximal safe set of the LROM. A hybrid backward reachability analysis is performed for this purpose. Considering a realistic scenario for PSA processes where the states are not available and the number of measurement sensors is very limited, the desired states are estimated...
Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes
, Article Scientia Iranica ; Volume 26, Issue 1A , 2019 , Pages 273-282 ; 10263098 (ISSN) ; Joghataie, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the...
Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes
, Article Scientia Iranica ; Volume 26, Issue 1A , 2019 , Pages 273-282 ; 10263098 (ISSN) ; Joghataie, A ; Sharif University of Technology
Sharif University of Technology
2019
Abstract
In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the...
Toward A Safe, Assured, and Dynamic Communication Protocol Stack
, Ph.D. Dissertation Sharif University of Technology ; Jalili, Rasool (Supervisor)Quantitative-Based Safety Evalution in the Primarly Stages of the Project Life Cycle
, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davoud (Supervisor) ; Bozorgmehri, Ramin (Supervisor)
Abstract
Inherent safety means that the process is naturally safe and the conditions of occurrence of unsafe cases and situations are eliminated from the system so that unsafe conditions can be controlled and prevented from occurrence by means of layers of protection. In general, evaluation of inherent safety may be studied in two different conditions; the first one is associated with the units that are not completely designed and built yet. In the initial steps of developing a process, there is much freedom in the determination of materials, equipment, and designing variables. As soon as the process enters its life cycle, making changes in the process will be very difficult and expensive. Therefore,...
A Robust Metamodel-based Simulation Optimization Approach for a Multi-Product Supply Chain Problem
, M.Sc. Thesis Sharif University of Technology ; Mahlooji, Hashem (Supervisor)
Abstract
One of the popular problems in the area of supply chain management is how to determine the critical decision variables in supply chain systems. This problem has been investigated by means of various methods one of which is simulation optimization. Due to the uncertain nature of real world systems, robustness of the resulting solutions is a worthy issue to be considered. In this effort, the problem of determining the safety stock levels in a multi-product supply chain system is addressed, a proper framework to define the decision and environmental variables is proposed, and their effects on the performance measures is investigated. A robust metamodel based simulation optimization approach...
Inherently Safer Synthesis and Optimization of Chemical Processes
, M.Sc. Thesis Sharif University of Technology ; Rashtchian, Davoud (Supervisor)
Abstract
There are different well-established strategies for making a process plant inherently safer. The benefits of applying these strategies on reducing the overall risk inside a plant are obvious. However, some of these changes are rejected many times because they appear to be too costly. But if the effects of applying inherently safer design strategies are investigated not only on the processing costs of a plant but also on the potential accident costs, the decision would in fact be different. In this paper an optimization procedure is proposed which integrates both processing and accident costs for different design schemes. In this procedure, some of the design variables are chosen with regard...
, M.Sc. Thesis Sharif University of Technology ; Hajji, Alireza (Supervisor)
Abstract
This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve...
Deformation and Stability of Dam Abutment due to Seismic Loading
,
M.Sc. Thesis
Sharif University of Technology
;
Ghaemian, Mohsen
(Supervisor)
Abstract
One of the most important aspects in the stability of arch dams which have been encountered, are the stability of the abutment. In order to assess the stability of wedge, Londe Method has been considered by simple assumption. Displacement and velocity of the wedge were calculated by Newmark beta method. In this study stability of abutment of Luzzone dam due to static and seismic loading was investigated. After modeling a finite element of dam-foundation-reservoir of Luzzone dam, the horizontal and vertical earthquake was applied to the model and the thrust force was recorded. By using a software stability safety factor of wedge was studied.it was found that the wedge is unstable and will...
Development Of a Software For Fault Tree Analysis By Modularization Method And Dynamic Classification Events with case study And Compared Results with the SAPHIRE Software
, M.Sc. Thesis Sharif University of Technology ; Ghofrani, Mohammad Bagher (Supervisor) ; Ebrahimi, Behrooz (Co-Advisor)
Abstract
Because of the Complexity in Calculating the Probability of Failure of the System, This Computation is Done by the Software Have Been Developed for this Purpose. Of Course, When We Use Them, We See That Each of Them Have Their Advantages and Disadvantages. One of the disadvantages that have been tried to be resolved over time, the type of programming and algorithm for calculation of it is the fault tree Because new techniques like modularization which have been designed in recent years, a significant improvement in accuracy and speed performance computing applications that use this method have been obtained.In This Thesis Has Developed Software That is Able to Calculate the Probability of...
Comparative Evaluation of Geometric Shapes for Aircrafts Standard Separation in Air Traffic Management
, M.Sc. Thesis Sharif University of Technology ; Malaek, Mohammad Bagher (Supervisor)
Abstract
In today's complex engineering systems, any increase in efficiency naturally comes with concerns about accepted level of safety. As demand for aerial transportation is increasing, more researches are conducted to increase the capacity of current controlled airspaces; as the limited capacity of the so called "en-route" corridors appears to be the main concern in the industry. Meanwhile, a solution is expected to be in more efficient exploitation of the current airspace capacities via optimizing the standards related to maintaining Separation Minima (SM) among flying aircrafts. Current standards assume an aircraft to be at the center of a circle with a radius equal to 5 nm. In this work,...