Sharif Digital Repository

Supplier selection and order quantity allocation problem is one of the most complex making decision problems comes into account. In the past, supplier selection done based on criteria such as price, quality and delivery time. Today's supply chains with the aim of expanding business activities and improving their performances, Follow process such as outsourcing, product development, and selection of multi-supplier strategies. This conditions will bring opportunities and threats for supply chains. One of the possible risks to supply chains are disruption risks and disruption has been a great concern in the past decade and disruption of suppliers are one of the new topics that have recently... 

One of the features of a project is its uniqueness, if two sets of activities are the same neither of them will longer be included in the project definition. A method in two projects with the same nature may yield inverse results of each other. Therefore, it is necessary to study the parameters affecting the project carefully before any action. So far, some research has been conducted in this area and it has been tried to perform case study on qualitative and quantitative parameters of the project. By investigating a number of common factors in most civil engineering projects, especially megaprojects, the present study attempts to identify and examine exquisite and effective parameters and... 

Ship maneuverability is so important from different aspects. According to the regulations of International Maritime Organization (IMO), every vessel has to meet the minimum requirements of mentioned rules. Consequently, prediction of ship maneuverability in early stages of ship design has become to one of the most necessary steps for shipbuilding and design companies. There are a variety of options in order to prediction of maneuverability of vessels, for instance, one important way is Free running model tests which is capable of direct calculation of the required parameters, provided if some certain conditions are met. In this work, firstly, an introduction to the importance of vessel... 

Sonoluminescence is a unique phenomenon in physics, which is known as the process of converting sound into light. By applying sound to a volume of liquid, with a specific geometrical shape (such as sphere) and forming standing waves around an existing bubble, the bubble first expands to a maximum radius and then gets extremely small leading to its supersonic collapse. During the collapse, the resulting shock wave approches the center of the bubble, causing extreme increase in the pressure and temperature at the center of the bubble. This causes flashing of light during small time scales (pico-seconds). This phenomenon is used in many fields, such as treatment of cancer. Also, the energy... 

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... 

The microstructure and wear performance of WC/Cu-Zn-Ni composite surface coating has been investigated using a combination of microscopy, hardness, and wear testing. The oxidation behavior of tungsten carbide hard metal in the temperature range between 600 and 900 ◦C was also researched. The oxidation mass gain of WC correlated almost directly with temperature as well as time. The particle of hard metal is surrounded by the α Cu+β Zn phase in the surface coating. The size of hard metal is almost unchanged from its original one. There exists an inter-diffusion zone at the interface of the hard metals and Cu-based matrix. The wear volume of the WC/Cu-Zn-Ni composite surface coatings increased... 

The growing requirements for renewable energy production lead to the development of a new series of systems, including wave and tidal energy conversion systems. Due to their sensitivity and the impact of the aggressive marine environment, the selection of the most adequate location for these systems is a major and very important task. Several factors, such as technological limitations, environmental conditions, administrative and logistic conditions, have to be taken into account in order to support the decision for best location. The aim of the present study is to provide an Atlas of IRAN Offshore Renewable Energy Resources (hereafter called ‘the Atlas’) to map out wave and tidal resources... 

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... 

At the present, End-stage renal disease(ESRD) is the ninth-leading cause of death in the USA.according methods of medical treatment for End-stage renal disease (ESRD), transplantation is the most viable renal replacement therapy for ESRD patients, there is a disparity between the demand for kidneys for transplantion and the supply. Incompatible inblood-type and antigen matching between patient-donor pairs is cause of shortage in disparity between the demand and the supply.paired kidney exchange of kidney among incompatible patient-donor pairs.PKE can be solve many difficulties in matching patient with incompatible donors. Kidney transplant surgeries in PKE must take place simultaneously... 

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... 

The aim of Emergency Medical Services (EMS) is to provide fast medical care and to transport patients to hospitals at the earliest possible time, so as to reduce injury and fatality rate. Healthcare managers try to improve healthcare systems by reducing the response time to demands. In this thesis, we present mathematical models for the problem of location and relocation of emergency vehicles after the end of their service time or after they have returned to a hospital. We believe that implementing these models can help managers improve the performance of emergency medical services. In the first part of this study, we present a two-level deterministic optimization model considering demand... 

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... 

Operating rooms have always been the most expensive and also the most profitable section in hospitals which include approximately one third of cost and two third of income. The management always wants to decrease the cost of hospitals. On the other hand, usually this goal stands against other goals such as patient’s satisfaction. So the manager should make a balance between these goals. In this research, we will propose an integer programming model for operating room scheduling problem without uncertainty for elective patients. In order to make the model more realistic, we want to make connection between operating room theatre and intensive care units. Also, we will consider desirable...