Sharif Digital Repository

Efficient processor allocation and job scheduling algorithms are critical if the full computational power of large-scale multicomputers is to be harnessed effectively. Processor allocation is responsible for selecting the set of processors on which parallel jobs are executed, whereas job scheduling is responsible for determining the order in which the jobs are executed. Many processor allocation strategies have been devised for mesh-connected multicomputers and these can be divided into two main categories: contiguous and non-contiguous. In contiguous allocation, jobs are allocated distinct contiguous processor submeshes for the duration of their execution. Such a strategy could lead to high... 

Reviewing the literature on air traffic flow management shows that reducing flight delay is one of the main challenges facing air transportation systems. This is due to the high cost of incurring delays. At the first stage, two mixed integer-programming model is presented here that aims to minimize delay cost of air traffic. The first presented model seeks to minimize flights delay costs by choosing an optimal airport configuration and balancing departure and arrival flights and the second presented model solve this problem with the new approach with categorizing the airplane by types and prioritizing them. Numerical examples are solved in CPLEX 12.6 to evaluate models performance. Numeric... 

Unglazed Transpired Solar Collectors, recently called "Solar Wall", are known as the most efficient solar air heating system for the past two decades. The equator faced collector which is installed in this system has many tiny perforations to suck in the air with a fan and gain the absorbed heat by the collector. Convection and Radiation heat losses from the absorber to surrounding and other design factors have different influents to the heat gain of this system. In this study, Continuity, Momentum and Energy equations are written with proper boundary conditions, solved with computational fluid dynamics methods and validated in order to model Solar Wall system. Thus we could compare all... 

In this study, the aerodynamic flow behavior in an low Reynolds number regime (Re = 1e3) around a tandem configuration is numerically investigated. In such conditions, the flow exhibits characteristics such as laminar behavior, separation bubbles, and high sensitivity to geometric parameters. Initially, using the finite volume method and solving the steady-state Navier–Stokes equations, the flow field around two consecutive airfoils was simulated. The aim of this step was to quantitatively and qualitatively examine the effects of spacing and angle of attack on flow characteristics, including pressure distribution and drag/lift coefficients. Subsequently, the numerical data were used to train... 

The picosecond (ps) pulses in a synchronously pumped optical parametric oscillator (SPOPO) is generated by a 20W and 81.1 MHz Yb fiber laser at 1064nm, providing 11.7 W of total average power in near to mid-IR at 73% efficiency so that the signal pulse with a wavelength of 1560 nm and 7.1W average power and 3330 nm idler pulse with an average power of about 4.6W has been produced. The optical parametric oscillator (OPO), based on a 50 mm MgO:PPLN crystal with 5 gratings which is capable of withstanding large average powers without thermal effects.
The duration of these ultrashort infrared signal pulse generated by the described SPOPO is measured by using homemade interferometric... 

In recent years, requirement engineering and goal modeling have gained more attention among different organisations. Therefore, different methods have been designed to discover stakeholders’ requirements and translate them into process and organizational goals. Various goal models have been introduced to represent these goals and their relations towards each other. Still, these methods are manual representations of different process scenarios and do not relate to the actual behavior. In 2014, Map Miner Method (MMM) was introduced to discover intentional process models from event logs. MMM uses Hidden Markov Model (HMM) as a means to represent the process as a map model of strategies and... 

Recommending routes to city taxis in order to improve their performance in finding passengers can reduce traffic, pollution and waiting time for passengers, as well as this, increasing the efficiency of taxis can increase their income. In this study, by analyzing trajectory data obtained from 536 taxis in San Francisco over a period of one month, we generated networks of cells, each of which has time-dependent characteristics such as the probability of finding a passenger, the capacity of each cell, or the amount of demand exists is in the cell and the average speed of passing through that cell. also, the connections between these cells in order to make more use of the experiences of taxi... 

The purpose of the present study is to develop neural network estimation method for hybrid or panel data which have a combination of two cross-sectional and time series structures and because of the features of both structures, their use in different sciences offers many advantages; and the analytical methods for this data structure are also different from other one-dimensional structures, so different and specific regression models are presented for this data structure. However, in the artificial neural network method, modeling the development for this data structure is neglected, so in the present study, using the concepts of panel regression methods and their application to the... 

In this study, membrane distillation process was used for treatment of high salinity waters. The focus of this study is to simulate and build a setup of membrane distillation process. Since the membrane distillation process is based on the driving force of the temperature difference, the required temperature is provided by both the use of heaters and the use of solar energy. To increase the feed temperature by solar energy, a black polymer coating on the main membrane is used. The main membrane used in this process is PVDF polymer and the polymer coated on the surface is the PAN polymer. After simulating and constructing the laboratory setup, the influence of a variety of parameters on the... 

The human brain is the most sensitive and important human organ and surgery must be done with high precision and without risk. During surgery, brain tissue deform continuously due to gravity, out of the cerebrospinal fluid and the changing pressure of the cerebrospinal fluid and the surgical maneuvers. Because the surgeon has no direct view on brain internal, the ways to solve this problem is to pay attention. This method makes it possible to the surgeon see in the brain and the brain tissue deformation. This thesis method is based on biomechanical modeling. After forming finite element model from the pre-operative MRI, brain surface and volume datasets during surgery as a load, apply to the... 

One of the utmost important factors during salvage operation of drowned ships is raising velocity. Uncontrolled raise is a dynamic phenomenon which can lead to the sudden tensions, collapse in airbags or ships. Studing this issue helps the engineers which kinds of problems are more important during salvage operations. This study focus on modeling and analysis of raising movment of the ship with FLOW-3D and ABAQUS software.
In FLOW-3D environment, hydrodynamic analysis of rising movment of drowned ship has been done. We should mention that applied forces and velocities and other parameters from the FLOW-3D output should be passed IMCA Criteria to avoid uncontrollable raise. In ABAQUS... 

Profile Monitoring is a new research topics in the field of statistical process control. In many applications of statistical quality control, sometimes quality of a process or product described by a relationship between a response variable and one or more independent variables.The researchers call this relationship profile. The study seeks to demonstrate that monitoring profiles In addition, the industry can be effective in medical field and improves control of the patient's condition by a doctor. Profiles are usually modeled with a linear regression equation, non-linear or polynomial. finally, the results of this study, using actual data, models and methods to predict and control... 

Two experimental models were designed and tested to extract energy from vortex induced vibrations of a elastically mounted one degree of freedom rigid cylinder in the Reynolds range of 120000 < Re <220000. In the first model the amplitude and frequency of the movement was measured then a second model was designed to be tested in the Emam Hossein marine laboratory. The model was designed in a way that many of its properties like mass ratio, spring constant and damping coefficient were able to be altered. In this study the vortex induced vibration of an elastically mounted cylinder was scrutinized in high Reynolds and very low mass ratios for the first time and an amplitude ratio of 2.49 were... 

As a method of cancer treatment or improvement of cancer-related complications, external radiation therapy is prescribed by physicians, in case of detection of a tumor in a region of patient’s body. Over time, various techniques have been developed for external beam radiation therapy. Among which, Intensity Modulated Radiation Therapy (IMRT), due to its ability to adjust the intensity of radiation beams, has a higher capacity to generate appropriate dose distribution based on tumor size and volume and it is one of the most widely used techniques in cancer treatment centers.The core process in treatment planning is using appropriate computer algorithms which results in posing enough damage to...