An Integrated Model of Pricing and Production in Assemble to Order Production System

, M.Sc. Thesis Sharif University of Technology Taslimi, Bijan (Author) ; Modarres Yazdi, Mohammad (Supervisor)

Abstract

In this research, we consider an assemble-to-order production system which accepts order for multi-products. Demand is stochastic and price-dependent. We also consider a sale index that links demand of each period to the previous periods demand. The variety of products which use common parts makes this revenue management system complicated. Furthermore, since the price of each product can have an effect on other products demand, it causes price dependency among them. We model the problem within the framework of dynamic programming approach to maximize discounted profit of the firm during a finite and multi-period horizon. We develop an integrated system of pricing and production decisions...

Optimal fractal-scaling analysis of human EEG dynamic for depth of anesthesia quantification

, Article Journal of the Franklin Institute ; Volume 344, Issue 3-4 , 2007 , Pages 212-229 ; 00160032 (ISSN) Gifani, P ; Rabiee, H. R ; Hashemi, M. H ; Taslimi, P ; Ghanbari, M ; Sharif University of Technology

2007

Abstract

The depth of anesthesia estimation has been of great interest in recent decades. In this paper, we present a new methodology to quantify the levels of consciousness. Our algorithm takes advantage of the fractal and self-similarity properties of the electroencephalogram (EEG) signal. We have studied the effect of anesthetic agents on the rate of the signal fluctuations. By translating these fluctuations with detrended fluctuation analysis (DFA) algorithm to fractal exponent, we could describe the dynamics of brain during anesthesia. We found the optimum fractal-scaling exponent by selecting the best domain of box sizes, which have meaningful changes with different depth of anesthesia....

Nonlinear analysis of anesthesia dynamics by fractal scaling exponent

, Article 28th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS'06, New York, NY, 30 August 2006 through 3 September 2006 ; 2006 , Pages 6225-6228 ; 05891019 (ISSN); 1424400325 (ISBN); 9781424400324 (ISBN) Gifani, P ; Rabiee, H. R ; Hashemi, M. R ; Taslimi, P ; Ghanbari, M ; Sharif University of Technology

2006

Abstract

The depth of anesthesia estimation has been one of the most research interests in the field of EEG signal processing in recent decades. In this paper we present a new methodology to quantify the depth of anesthesia by quantifying the dynamic fluctuation of the EEG signal. Extraction of useful information about the nonlinear dynamic of the brain during anesthesia has been proposed with the optimum Fractal Scaling Exponent. This optimum solution is based on the best box sizes in the Detrended Fluctuation Analysis (DFA) algorithm which have meaningful changes at different depth of anesthesia. The Fractal Scaling Exponent (FSE) Index as a new criterion has been proposed. The experimental results...

Design of a Fault Tolerant ARM-Based Processor on FPGA

, M.Sc. Thesis Sharif University of Technology Esmaeeli, Siamak (Author) ; Rashidian, Bijan (Supervisor) ; Vosughi Vahdat, Bijan (Supervisor)

Abstract

The charged particles in space strike the silicon surface of an embedded system in a satellite and cause fault occurrence in its operation. So some methods should be employed to reduce the effects of the faults. The methods that are implemented in system level are widely used because of their low cost and high reliability. The processors are responsible for performing main processes in embedded systems. On the other hand, the ARM processors are good choices for utilizing in satellites because of their low size, low power consumption and high performance. Also, FPGAs have made a major improvement in embedded system design. So with implementing ...

Design of a Fault Tolerant SPARC Based Micro Processor On FPGA

, M.Sc. Thesis Sharif University of Technology Hosseini, Morteza (Author) ; Rashidian, Bijan (Supervisor) ; Vosoughi Vahdat, Bijan (Supervisor)

Abstract

In this thesis, LEON Processor was chosen for its compatible architecture that can be implemented on a wide range of FPGAs. The final designed processor is aimed to conquer soft and hard errors that occur due to cosmic radiations in SRAM cells of an FPGA. The system can finally resist all single SEUs that happen in flip flops and all 4 random errors that take place in each register of the register file. All the flip flops and latches are protected using a TMR scheme. The information redundancy in the regiester file to overcome all 4 random errors is 168% and the errors are corrected by means of a mechanesim that is masked from the processor core. In cache memory, each 32 bit data is...

Power-law correlation in human EEG at various anaesthesia depths

, Article IET 3rd International Conference MEDSIP 2006: Advances in Medical, Signal and Information Processing, Glasgow, 17 July 2006 through 19 July 2006 ; Issue 520 , 2006 , Pages 46- ; 0863416586 (ISBN); 9780863416583 (ISBN) Gifani, P ; Rabiee, H. R ; Hashemi, M. H ; Momenzadeh, S ; Taslimi, P ; Ghanbari, M ; Sharif University of Technology

2006

Abstract

The depth of anaesthesia estimation has been of a great interest in recent decades. In this paper we present a new methodology to quantify the depth of anaesthesia by quantifying the power-law correlations of the EEG signal. Extraction of useful information about the nonlinear dynamics of the brain during anaesthesia has been proposed with the optimum fractal scaling exponent. This optimum solution is based on the best domain of box sizes in the detrended fluctuation analysis (DFA) algorithm which have meaningful changes at different depth of anaesthesia. The experimental results confirm that our new algorithm on the raw EEG data can clearly discriminate between aware to moderate and deep...

Low Grade Heat Driven Multi-Effect Distillation and Desalination

, Book Rahimi, Bijan ; Chua, Hui Tong

Elsevier 2017

Abstract

Low Grade Heat Driven Multi-effect Distillation and Desalination describes the development of advanced multi-effect evaporation technologies that are driven by low grade sensible heat, including process waste heat in refineries, heat rejection from diesel generators or microturbines, and solar and geothermal energy. The technologies discussed can be applied to desalination in remote areas, purifying produced water in oil-and-gas industries, and to re-concentrate process liquor in refineries.
This book is ideal for researchers, engineering scientists, graduate students, and industrial practitioners working in the desalination, petrochemical, and mineral refining sectors, helping them...

Simulation of New Methods in Ventilation of Underground Station Sand Tunnels

, M.Sc. Thesis Sharif University of Technology Adibi, Omid (Author) ; Farhanieh, bijan (Supervisor)

Abstract

Due to growth of the number of passengers in subway transportation systemsthe capacity of the metro stations are on the rise.The generated heat loads in subway line shall be increased by thegrowth of the its capacity. As a result, current subway ventilation systems cannot provide comfort conditions for passengers. Nowadays, modern ventilation systems are designedto improve ventilation performance and to create suitable thermal conditions. Among of these, the under platform andover track exhaust systems and use of platform screen doors can be Cited. The aim of this study is three-dimensional simulation of air flow in modern ventilation systems of subway stations. Numerical simulations are in...

Numerical Simulating of a Railcar fire in Tunnel

, M.Sc. Thesis Sharif University of Technology Pourghasemi, Mahyar (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Fire phenomenon and its hazards through urbun transportation systems like subway is a major debate in management of these territories. Recently, varios factors, such as great deal of passengers whom travel by these systems, financial damages and psychological disorders due to fire accidents resulte in noticeable investigation to prevent and reduce these subjects. In this research, simulating of railcar fire has been conducted to estimate the amount of heat release rate (HRR) and parameters which affect on it by modelling behavior of combustible materials inside railcar. As regards to materials which are available inside railcar that participate in fire, their behavior face to heat flux has...

Simulation of Fire in Tunnels Using Fire Dynamics Simulator Code (FDS)

, M.Sc. Thesis Sharif University of Technology Shahsavan, Martia (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Designing of an efficient emergency ventilation system is one of the main approaches to prevent the perilous fire in tunnel phenomenon. For this purpose, firstly, fire behavior and its heat release rate should be investigated. Knowing about temperature distribution and smoke movement is the second step. One of the most considerable factors in smoke control is critical velocity. It means the minimum velocity to prevent backlayering flow. If longitudinal ventilation velocity were less than this amount, smoke and hot gases originated from the fire can enter the upstream zone. This may cause lack of oxygen and decrease visibility for the passengers when they are escaping from the fire field. In...

Numerical Investigation of Turbulent Flow Inside De-Oiling Hydrocyclones Using Large Eddy Simulation Approach

, M.Sc. Thesis Sharif University of Technology Saeedi, Maysam (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Hydrocyclones are used for separating different materials from liquids in a variety of applications. Compactness, efficiency, reliability and low maintenance costs are their noteworthy characteristics. Dewatering and deoiling hydrocyclones used for refining crude oil or oily waste water in offshore platforms are examples of liquid-liquid hydrocyclones. Separation process in hydrocyclones is based on the fact that swirl flow induces a centrifugal force and leads to separation due to density difference. The density difference in liquid-liquid mixtures is smaller than solid-liquid types and trying to separate one liquid from another takes much more effort than the other type. Increase of...

Thermionic Emission Properties of Oxide Based Nano-Structures

, M.Sc. Thesis Sharif University of Technology Heydarian, Hesam (Author) ; Rashidian, Bijan (Supervisor)

Abstract

For years, in thermionic emission, a great deal of scientists’s effort has been devoted to the search for low work function materials with high melting temperature. In this way, high brightness and long life are the central targets of emission material investigations. In addition, high current density and low power consumption are the guiding principles for some applications.
In first part of this thesis, basic electron emission theories, fabrication methods of thermionic emission, effect of different parameters on the electron emission properties of thermionic emitters and applications of them are investigated. After setting up fabrication methods of S type cathode, in the second part...

Deposition of Nanoporous Metallic Thin Films by Sputtering and Comparing with Electrochemical Method (Electroplating)

, M.Sc. Thesis Sharif University of Technology Monjezi, Hossein (Author) ; Rashidian, Bijan (Supervisor)

Abstract

Porous thin films have becom very atractive due to their applications in many types of electronic and optical devices. There are several methods for deposition of such films. Chemical method for deposition of nanoporous thin films are relatively simple, but usually hard to control. In this thesis, chemical deposition of thin porous Molybden films is reported. In addition, an available sputtering system has been modified and, controlled porosity thin films were then deposited on glass and silicon substrates using GLAD method.These films have been characerized, and compared with chemically deposited porous thin films

Evaluation and Simulation of Tunnel Mid-shaft Effects on the Natural and Normal Ventilation Performance in a Subway Tunnel

, M.Sc. Thesis Sharif University of Technology Mahmoodi, Ghasem (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Necessity of a public transport network, environmental protection and a highly land cost in urban areas have increased the desire for underground transportation systems. On the other hand, ventilation system design should be done precisely specially for longer tunnels, large undergrounds spaces and crowded places. Rate of energy reduction for vent systems operation is dependent on their proper implementation. Tunnel design efficiently is influenced by ventilation system. The tunnel mid shaft is complementary part of the underground railway systems that is required for exchange air between the tunnel and the railway station with ambient fresh air. An important application of the tunnel mid...

Simulating Firefighting Scenarios in Enclosures

, M.Sc. Thesis Sharif University of Technology Amiri, Pezhman (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Fire in enclosures is one of the most important disasters due to the presence of human and physical risks, so, investigation of the firefighting scenarios in this case has much importance. In the present study, novel enclosures fire suppression scenarios are simulated using computational fluid dynamics (CFD). The simulations have two major categories. In the first part, performance of different natural ventilation, positive pressure ventilation (PPV) and negative pressure ventilation (NPV) scenarios, which are new methods in firefighting, are evaluated and compared. In this part, the influence of different parameters like geometry, position of inlet and outlets and fire heat release rate...

Modeling of Urban Air Pollutants Dispersion

, M.Sc. Thesis Sharif University of Technology Moradpour, Mrayam (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Air pollution is lateral and inappropriate product of industry and technology development that grows along them, unfortunately. Now its domain extended from local and national issues to global issues. For years like other branches of environmental sciences and other scientific fields, scientists apply formulas and mathematical equations. Nowadays, air pollution modeling is fundamental and powerful tool for air pollution studies, especially in prediction of air pollution conditions, pollutants emission and their concentration under different conditions and arbitrary locations. In this research, numerical modeling of urban air pollutants dispersion is discussed. After validation of results,...

Analysis of CO Distribution in Large Tunnel Fires

, M.Sc. Thesis Sharif University of Technology Sojoudi, Atta (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Fire events and the related toxicants such as CO are responsible for many fatalities inthe current century. These hazardous events are more dangerous when they occur in enclosedspaces. In the present study, a theoretical relation is developed for horizontal distribution of COin a large tunnel fire. Then, developed criterion is used to study the effect of rudimentaryparameters such as Heat Release Rate (HRR) of fire and tunnel Aspect Ratio (AR) on CO andtemperature stratification. Theoretical results of various heat release rates and aspect ratios forhorizontal distribution of CO are compared with numerical results using Fire DynamicsSimulator (FDS5.5). It is found that big fires have higher...

, M.Sc. Thesis Sharif University of Technology Salari, Sina (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Centrifugal Fans are widely used in industrial and commercial applications, from shop ventilation to material handling to boiler applications. They consume extremely high amount of energy each year. Because of this high consumption, even a small efficiency improvement could led to high amount of energy saving. Many projects have been done with this goal up to now, and present work is one of them, with aim to optimize a industrial centrifugal BI fan performance, with wheel diameter about 400 mm. The research has been done based on 3D numerical methods, done by commercial code Fluent 6.3, in steady state. MRF and k-E models have been used to simulate flow around blades, and turbulence...

, M.Sc. Thesis Sharif University of Technology Shojaei, Mozhdeh (Author) ; Farhanieh, Bijan (Supervisor)

Abstract

Development of cities as well as population growth causes to development of public transportation especially subway lines. Fire is the one of the most important issues that may occur in subways. The difference in flame size, emission heat, smoke and pollutants generation of subway fires attracts an especial attention of fire investigators. The emergency ventilation of subways in the case of fire should have the ability of discharging heat, smoke and pollutants from passenger escape route and preparing a safe place for a specific duration. The aim of this research is simulating fire in subway stations and defining proper regional fire scenarios to prepare a safe route for passengers escape....

Fabrication of Metallic Nano-Tip Field Emitters and Measurement

, M.Sc. Thesis Sharif University of Technology Yazdanfar, Payam (Author) ; Rashidian, Bijan (Supervisor)

Abstract

The need for integration of electron guns together with thermal considerations of thermionic cathodes has led to design new cold cathode guns based on field emission phenomenon. In first part of this thesis, basic field emission theories, fabrication methods of field emitter arrays, effect of different parameters on the field emission properties of field emitter arrays and applications of these arrays are investigated. After setting up fabrication methods of nano-tip field emitters, in the second part of thesis, Si nano-tips and Si field emitter arrays are fabricated using of thermal oxidation of silicon substrate, lithography, and chemical etching of silicon oxide and silicon substrate. Si...