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... 

To reduce construction costs selecting the optimal route for water conveyance line entails ample observation and considering all effective parameters. Some part of Aidoghmoush dam project of water conveyance line located in Azerbijan the east has been investigated in this research. First, by investigating, effective factors in determining the optimal route have been identified and then categorized into two groups of quantitative criteria(technical-economical) and qualitative criteria(environmental). Quantitative objectives include: slope, transportation system, infrastructures, fault and soil type. Qualitative objectives include: environmental considerations, land use and land cover. Because... 

Nowadays, by development of technology and population, rivers have been faced environmental issues. In one hand, due to the several factors that can affect rivers pollution, it is not easy to propose a comprehensive solution for the above mentioned issues, while, on the other hand, it is necessary to address and resolve some of these issues as soon as possible. Considering rives as a system, there are lots of economic, political and quite a few other factors which try to change the condition to their own interest. In order to find a solution that satisfies all the effective parameters up to a certain limit, a mathematical tool, called the Game theory method, is utilized. In this research, we... 

In this thesis attempted to present practical hydro-aerodynanic model with low computational time and high accuracy for WIG craft with a compound wing, a catamaran hull form and a power augmented ram (PAR) platform at take-off phase. To achieve this innovation, aerodynamic and hudrodynamic model are coupled and dynamic air cushion between demi hull of catamaran under the wing was considered by modeling PAR platform with effect of flap. To validaty the results of hydro-aerodynanic model, two test models were producted and the results of hydro-aerodynanic model are compared with the experimental results that the presented results had good agreement with the experimental results. Influence of... 

The design and optimization of processes was focused in the past on economic issues such as profitability and return on investment, and less attention has been paid to environmental issues. In recent years, by introducing environmental criterion as pillars of sustainable development, environmental optimization of processes has becoming an inseparable element of the process engineering. Therefore, it is necessary to examine the compatibility of environmental indicators with economic objective. The purpose of this study is to investigate environmental indicators and economic objective function in optimizing the Crude Distillation Unit (CDU) of an oil refinery. The CDU is one of the most... 

Drilling operation is one of the most important parts of oil production procedure. Therefore, drilling optimization has an effective role in ultimate benefits and total cost reduction. Also formation damage can affect reservoir performance. In this study, a combination of optimization methods for each part of drilling operation has been used and fitness function of total cost is presented. This function includes number of bit runs, bit selection, controllable parameters and drilling mud properties. For prediction of formation damage radius and variable risk analysis, two new methods are proposed and have been used as fitness functions. Finally, by suggesting a multi objective optimization... 

In this thesis, the optimal trajectories of a spacecraft in the binary asteroids system is studied. The objective functions of optimal trajectories in these system are the maximum coverage of the asteroids surface and minimum time and fuel consumption. For this purpose, the dynamic of binary system is modeled. The binary system of 1999 KW4 is selected as a case study. The ellipsoid-sphere model is a good approximation for the case of this study. In this model, the asteroids orbit in a circular orbit around each other in a spin-spin-orbit resonance configuration, in which the asteroids’ rotational velocity is equal to orbital mean motion. Then, the equations of motion of the spacecraft as the... 

The robot considered in this project is to test parts and equipment installed in marine vessels under sea movements and waves. After a thorough assessment amongst common solutions to problems of this kind, a Stewart-Gough based manipulator has been chosen so that all the requirements could be satisfied. Therefore, according to the information obtained through relevant organisations, the purpose of this project is to work on dynamics, control, and design of the structure of a 6DOF Stewart platform – based hydraulic motion simulator for heavy payloads for samples weighing up to 2.5 tons which can handle linear accelerations up to 10 m/s2, rotary accelerations up to 150 º/s2 performing at a... 

Nowadays, Automation and Robots have many industrial and non-industrial applications. One of the most important of Robotic applications in industries for speed increasing, is utilizing them for packing procedures on production lines. Speed and accuracy enhancement, low-error repeatability, and cost reduction are benefits if using robots. Delta robot, is one of the parallel robots which is consists of three arms each connected to universal joints at the base and can reach high speeds.Delta robot can be optimized in 1. Performance speed, 2.accuracy, 3. Maximum payload, 4. Workspace and dexterious workspace and 5. Costs reduction. Since it’s not possible to fully optimize all goals... 

Pistachio trade in Iran is of great importance in non-oil exports, and this country has been the main producer of this product for many years. In recent years, unfortunately, pistachio products have fallen sharply in the country, and on the other hand, the United States has been able to take a large share of the global market. The researchers have presented numerous reviews about the causes of this problem, most notably drought and water scarcity, inefficient agriculture, and the lack of comprehensive and efficient management of the pistachio supply chain. In this research, to address these problems, attention has been paid to sustainable supply chain management that addresses three... 

Given the importance and the need to strengthen the agricultural sector within the national development strategy, it is necessary to meet the different needs of the agricultural sector in different areas. Since the activities and diversify the agricultural sector, the industry must be tailored to geographic locations.Unlike the studies so far, we in this research in order to achieve a proper and efficient planning, effective dimensions of the chain as an integrated review and a network of supply chain, production and distribution of agricultural products, livestock and processing industries have designed, so that we can have a comprehensive plan for each of the sectors of agriculture,... 

One of the main and challenging stages in the development of hybrid vehicles (HEVs) is the conceptual design of its powertrain, which includes two parts: architecture design and sizing. This research aims to introduce a novel framework for conceptual design of HEV powertrains. By using this framework, not only the sizing of components is optimized but also the optimal architecture of powertrain is selected. In the proposed framework, by finding the optimal values of the powertrain design variables, including type of architecture and sizing variables (such as nominal powers, nominal torques, conversion ratios, etc.), the performance and the cost of hybrid vehicle is optimized in three layers... 

Growing concerns towards social and environmental issues besides economic in supply chain causes that the sustainable supply chain become one of the most important concepts in a supply chain. Likewise, a supply chain network design which is profound influence on long-run economic, environmental, and social decisions is one of the key and strategic topics in a supply chain. In this study, we represent an integrated approach for a three-layer sustainable supply chain network design with routing and different transportation modes, the objectives of which are minimizing total costs, a minimizing 〖CO〗_2 emissions of transportation, and maximizing total values of social purchasing. In this... 

Real-world decision-making problems usually have several criteria for evaluating the performance of alternatives. On the other hand, mathematical programming is a very practical tool for modeling and solving decision-making problems and multi-objective mathematical programming has high importance among researchers and managers in this field of study. However, the field of multi-objective integer programming is considered a rigorous category. Methods for solving these types of problems can be divided into three different approaches. There are few approaches and methods for solving multi-objective mixed-integer optimization problems in litreture.In this research, an extension of benders... 

Technological progress, complexity in costumers’ needs and distributed resources make extreme competition in business environment. It produces some novel concepts. In this research, we concentrate on cloud manufacturing which was generated by using cloud computing concepts and focuses on resources sharing between various manufacturers. One of key problems in this field is service composition. In this work, I have proposed a mathematical model with binary variables for service composition problem in multi-cloud manufacturing environment. In this model, I’ve considered for qualities of services (cost, time, energy, reliability) as objective functions. Cost and time functions include the cost... 

In this research, multi-disciplinary design optimization (MDO) of a flying vehicle has been done based on the flight simulation. A meta-heuristic algorithm called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA) has been used for optimization. Since solving a MDO problem is a time consuming process, a RBF neural network has been used in the optimization algorithm as a surrogate model. The new algorithm, called MARCOMA+NN, has been tested with some standard benchmarks. MDO problem has six disciplines consists structure, aerodynamic, propulsion, guidance, control, and fire control. The MDO problem has 31 design variables and two objective functions. The objective functions are... 

This paper presents five origin-destination (OD) flow estimation models using traffic sensors. The first model uses counting sensors data, the second model uses automated vehicle identification (AVI) sensors data and the third, fourth and fifth use combined data of counter and AVI sensors simultaneously. The first to fourth models are bi-level problems that the upper-level minimizes some objective functions where is the distance between estimated flows and observed flows. On the other hand, the lower-level problem finds user equilibrium (UE) flows pattern for estimated origin-destination matrix (ODM). The fifth model is a multi-objective problem, where a bi-level problem is solved for each... 

An important step in the early stages of an oilfield development is the accurate identification of the location of production and injection wells which has a significant impact on productivity and profitability of the reservoir. Recently, operation companies in petroleum industry focus on production optimization, recovery enhancement and cost reduction; as a result, application of non-conventional wells (NCW) or non-vertical wells have dramatically increased. Well placement optimization is a complicated task as it is a function of several contributing factors including reservoir heterogeneities and economic constraints. The complexity of this task increases when it is considered as a... 

The aim of this paper is to propose a scheduling method to consider reliability along with makespan in grid computing systems. The reliability of task execution is considered in the proposed method to increase the chance of running large-scale and computationally intensive workflows successfully. To handle situations in which a resource failure in a possible scheduling solution occurs, the proposed method finds a collection of scheduling solutions instead of only one solution to run the workflow. It leads to have chance to run an alternative scheduling solution that is not using the failed resource. To find the most optimized scheduling solutions, we exploit the lately developed... 

Multi-disciplinary design optimization (MDO) of a surface to air flying vehicle has been done in this research, on the basis of flight simulation. The MDO problem have five disciplines consists of aerodynamic, propulsion, guidance, control, and fire control. Multiple campaign scenarios are defined. The MDO problem has 31 design variables and two objective functions. The objective functions are flying vehicle weight and miss distance. A new meta-heuristic algorithm has been designed to solve multi-objective optimization problems. The new algorithm has been called Multi-objective Adaptive Real-coded Memetic Algorithm (MARCOMA). The MARCOMA can solve large-scale and multi-objective problems and...