Sharif Digital Repository

A common decision in project management is the selection of contractors to simultaneously optimize three objectives of the project’s triangle. This issue becomes more important if there is more monetary value involved or there is limited number of capable contractors. In project planning, there is numerous choices for tasks; each with specific time, cost and quality. There is no trade-off problem, if one of the choices has the best time, cost, and quality, simultaneously. However, as these criteria do not generally work in a unique direction, it makes the selection decision difficult. A contractor who performs the projects on time may have higher cost and lower quality. Given that there is a... 

Planar visibility computing is defned as determining the region of the plane that is visible from a specifc observer. This concept has many applications in computer graphics, robotic and computer games. In certain visibility problems, counting the number of visible objects in an appropriate time is required. For obtaining a solution fast, current algorithms give an approximated count. In this thesis, we consider visibility testing problem and visibility counting problem.For a given set S = fs1; s2; :::; sng of non-intersecting segments and a query point p in the plane, the visibility testing problem checks the inter-visibility of p and a segment si 2 S and the visibility counting problem... 

The focus of this research is to present a model to verify the acceptance of projects with time and cost dependency on the usage of equipments. Decision on these projects is based on a dynamic programming in which at each stage, the profit of available projects in this stage, equipment value and the best choice of future stage are decision keys. In other words, after the completion of a project, it should be decided between doing a project or selling the equipment and leaving the remaining projects. For each projects, there is a product network that includes projects jobs and operations. After accepting projects, equipments of the projects will not be renewed and the usage of the equipments... 

Injuries of neuro-musculoskeletal system impose large costs to the modem societies. Studying the strategies of CNS in planning and control of movements can be helpful in developing diagnoSiS, prognosis and treatment procedures in clinical view and also in designing rehabilitation system and humanoid robots. Tow important features of human movements are redundancy problem and structured variability. Previous studies solved the redundancy problem mainly with optimization methods. Also optimal feedback control theory is the only method that successfully modeled structured variability in voluntary movements. Despite the appropriate outputs this methods are not based on physiological facts... 

Lifting is considered a major risk to people's health in life, particularly to the workers. Appropriate wearable tools for measuring the individual’s kinematic and kinetic movement are required for examining and analyzing the lifting activity to prevent injury in the workplace. Different wearable systems have been developed to calculate the force applied on the foot sole to analyze movement in various areas of gait analysis, occupational biomechanics, sports, and other areas. The accuracy and precision of these systems need to be tested before application in any of these areas. In this study, 3 subjects performed five different activities of symmetrical lifting by placing Pedar insoles in... 

Turan Toad-headed Agama is a lizard (Phrynocephalus mystaceus) inhabiting in the deserts of the Middle East. In order to hide from predators, it laterally vibrates (and slightly oscillates around the dorsal axis) to descend beneath the sand. Despite its low density, toad-headed agama easily burrows beneath the sand. The purpose of this study is to initially determine 3D kinematics of the agama's burial technique (frequency, amplitude and position of critical points of the body). After determining the motion, we will figure how the motion interacts with granular media and enables the animal to burry. This includes simulating animal's motion within granular media using discrete element method... 

In recent year carbon nanostructures (CNS) has been the pinnacle of academic and industrial research. After development and refinement of better methods of controlled fabrication of high-quality CNS, these structures started substituting nanotubes in their renowned applications including nanochannels and nanocarriers. Due to the tunable core size of CNS using electric fields, they can be used as controlled ion channels and nanocarriers with controlled drug release as well as more dynamics oriented applications including nano-oscillators, nano-actuators and artificial muscle tissue. However lack of vibrational studies on CNS has hindered researchers in this path. In this thesis vibrational... 

Water resources planning and management projects are done in order to accomplish several goals. Moreover, social, environmental, political etc impacts of such projects increase the complexity of the problem of choosing the best alternative among others. The project of diversion of water form Zab Watershed into Lake Urmia Watershed is one of these projects which regarding water demands and problems in Lake Urmia Watershed and also Zab Watershed water resources that exceed its water demands has been considered. Therefore, after conducting research studies, five locations have been determined as potential places to build a dam on the Zab River and transferring its water to Lake Urmia Watershed.... 

In this research, we propose a formulated approach to locate and allocate two level of a three-level closed-loop supply chain consist of a number of capable points production facilities, redistribution centers and customer clusters for multiple products in multiple time periods. Also, we consider environmental aspects in this supply chain network by taking into account an objective function, aside from cost objective function, in the template of emitted carbon dioxide. In this research for the first time we consider vehicles’ emitted CO2 different in each period which is a result of gradual depreciation of vehicles. In the end for the sake of validating model’s performance we developed few... 

Cyclic distillation can bring new life in old distillation columns, by using a periodic operation mode that leads to significant benefits, such as increased column throughput, lower energy requirements and much higher separation performance. The design method for this type of column are reviewed. Among two design approaches, the Lagrangian one is selected, where equations are formulated as delay differential equations, moving from bottom to top of the column to determine feed tray location and total tray numbers. No rigorous design method is selected in order to calculate the column parameters.In this thesis, by defining an economic index that encompasses capital investment, operating costs... 

In this project, we use a novel mechanism to control the lumbar rotational profile and also the disc pressure of L3/L4 and L4/L5. Spine, as one of the most important parts of human musculoskeletal system, helps human beings to walk on two feet without much energy consumption. Any problem in this part may cause moving disorders or pain. To heal severe spine disorders, many different methods like surgery and implantation are adopted. To be sure of proper functionality in the human body, these methods should be tested clinically in advance. Cadaver spine testing in vitro, is accepted as a gold standard to evaluate new methods. One of the main challenges facing spine in vitro tests is how to... 

One of the best stimulation methods for oil and gas wells is matrix acidizing in order to increase the near wellbore permeability. in acidizing, good acid coverage in different layers is one the main goals. so, various methods have been presented. important part in using these methods is to not damage formation and economic matters. modern methods utilize VES acids for this purpose. viscoelastic characteristics of these materials by formation of miscellaneous, increases the apparent viscosity by a large degree. for this reason, VES fluids can be used to improve acid divergence in acid injection operation. acid system based on viscoelastic surfactants that is changed to gel instantly, can be... 

In recent years, emerging Non-Volatile Memories (NVMs) have become promising alternatives for existing memory technologies. Due to shortcomings of SRAM memory in nanometer era,NVMs such as Phase-Change Memory (PCM) can be used in configuration memories of Field-Programmable Gate Arrays (FPGAs). Despite prominent features of emerging NVMs, they suffer from high write-power, high write-latency, and limited number of reliable write opera-tions. In addition, a dedicated Peripheral Circuit (PC) which is required to convert the NVM state to the equivalent voltage level can impose significant area and power overheads to FPGAs.In this thesis, a reliable power-efficient hybrid architecture employing... 

In this thesis a nonlinear thermomechanical model based on Lagrangian-extended finite element method is proposed to simulate discontinuities under thermal and mechanical loads. At first, a geometrically nonlinear model is presented for large deformation problems and then the model is completed by considering thermomechanical aspects. In extended finite element method, different enrichment functions are stated and also using analytical methods, a new set of functions are introduced to enrich the temperature filed around biomaterial crack tips. For numerical simulations, an object oriented code is created in C++. The results of numerical simulations are verified by the use of ABAQUS  

Every day requirements for oil, gas and exploration in deep water have pushed offshore industries into deeper water. Oil production is expensive, so a designed platform should be cost saving. The clear and logical part is that, testing a model will be an important part of these kind of researches. In this thesis we are trying to obtain numerical results from ANSYS AQWA and experimental results for surge, heave and pitch motions, then compare experimental results with numerical one. Second order effects are ignored in designs and experiments because of laboratory conditions and limits that we are faced with in there. 1/250 scale ratio has been chosen because of limits. First we get into... 

Discretely holomorphic observables have recently been proposed for two dimensional lattice models at criticality, whose correlation functions satisfy a discrete version of Cauchy-Riemann relations. Existence of these observables appears to have a deep relation with integrability of the model. On the other hand at critical points of these models, there exist entities known as discrete parafermions whose Boltzmann weights satisfy the Yang-Baxter Equations. For this reason, finding parafermionic observables in any lattice model is equivalent to proof of solvability. This thesis is a step towards understanding the relation between Parafermions and Solvability. For instance, the Boltzmann weights... 

Insulin pump treatment is considered the most physiological way to imitate the healthy body's insulin profile in patients with diabetes. They provide a precisely controlled rate of insulin delivery to diabetic patients who would normally need multiple daily injections to regulate blood glucose levels. The firmware allows numerous modifications to the bolus dose and basal rate to enable patients to manage insulin levels in response to events such as eating, sleeping, and exercise.
In this Study, we have first investigated different models of insulin pumps on the market and chose the Spring ZoneTM insulin pump model for our study due to its innovative technology. This pump employs a...