Sharif Digital Repository

Cost Estimation plays an essential and role in UAV (Unmanned Aerial Vehicles) Projects. By increasing the complexity of new unmanned systems, the importance of this task augments. Additionally, up to now, a comprehensive approach has not been adopted internationally. But in parallel a number of international companies and organizations has developed specific methods by themselves; confined to their corporate.
This project pursues developing a complexity-based model for cost estimation of unmanned aerial vehicles, especially Jet UAVs. However, it’s anticipated that this model may be utilized for all kind of systems, but it seems that jet UAVs use it with a better and more reliable... 

Arising from the intersection of two modern ideas in logic and mathematics, namely Type Theory - specifically Martin-Löf’s intuitionistic type theory, and Homotopy Theory, Homotopy Type Theory has introduced a novel formalism that formalizes every mathematical object - including constructions, definitions, and proofs - in a specific and fundamentally different way from other interpretive frameworks (such as set theory), bringing forth new results - both philosophically and mathematically. The first goal of this research is to understand the meaning of Homotopy Type Theory as a foundation for mathematics through exploring this new formalism. The second goal of this research is to understand... 

One of the crucial matters in the area of Supply Chain Management is the ability of a supply chain to act and react under different circumstances. A helpful tool to understand the supply chain is simulation modeling. With the help of simulation modeling, we can provide the opportunity for the agents in a model to perform based on the defined environment.In the current research, a complete literature review is performed on the topics of supply chain planning and various distribution models and algorithms. With the focus on the vaccine as a critical item, we propose a model to distribute vaccines based on the degree of agents, and we realize that vaccine distribution, while facing huge demand... 

Numerical study of the interaction mechanism of the premixed flame and the acoustic field is performed in this work. The geometry similar to those used in experiments, is a two-dimensional tube in which flame travels form open end towards the closed end. The numerical study is done using PPM method. Results show that the shape and speed of laminar flame is strongly affected by the induced acoustic field. Stronger interaction is observed in the closed-end tube with no slip boundary conditions. The effect of the Lewis number on the interaction mechanism is also investigated. Premixed flame- accelerated flame – interaction of flame and acoustic field  

Translation quality assessment (TQA) as a systematic field of inquiry has been under scholarly investigation over the past decades. In spite of the challenges appeared in the path to success, theoretical and practical developments have already been made in translation studies. One of the unsettled and challenging problems concerning translation assessment, yet, is the subjectivity that is inherent in the process of scoring test-takers’ translation performances. In the absence of any granular objective criteria which includes all the subcomponents of translation as a multi-layer rather than unitary construct, the raters inevitably bring their intuition and will to the act of measurement.... 

Knowing the location and time of oil accidents and trying to track the pollution caused by these accidents is very important for the purpose of monitoring and protecting the environment. The occurrence of large oil spills in the marine environment can have serious environmental, social and economic consequences. In this research, oil spills in the Persian Gulf were first identified using remote sensing method and Sentinel-1 satellite images. The images of this satellite were called for the processes needed to identify oil spills in Google Earth Engine space. After detecting the oil spills, it is necessary to determine the duplicate spills and remove these types of spills, as well as estimate... 

In this paper, we introduce a novel decision making strategy on how to assign markets to a multi-item newsvendor’s problem. We present a new formulation method based on the integration of news-vendor problem and dynamic programming approach alongside an efficient solution method. Suppose there are n distinct products and corresponding time intervals for selling them in different markets. These products will be worthless (perishable) at the end of each interval. Our proposed framework represents a trade-off between costs associated with staying in a market for further periods and costs of relocating the business in a new market. The objective is to maximize the total profit of our decisions... 

Nowadays, with the increasing number of polyethylene terephthalate wastes, the issue of its recycling has become very important. Among the problems of polyethylene terephthalate recycling are its loss of crystallinity and mechanical properties. Recycled polyethylene terephthalate does not have the properties of new polyethylene terephthalate and using its mixture with other materials is an effective way to remove its waste from nature and return it to the production cycle. The aim of this study is to produce a mixture of recycled polyethylene terephthalate with polycarbonate and glass fibers with mechanical properties such as good impact strength, which ultimately leads to the production of... 

In the current digital era, the large number of mobile developers and android applications has led to intense competition. Users can easily access many android applications to meet their needs. This abundance of available software makes it difficult for developers to attract and retain users, as they can easily switch from one application to another. This switch can happen if the current application does not meet the user’s needs, has issues, or if a better alternative is available. Therefore, developers must focus on keeping their users satisfied. To ensure user satisfaction, developers need to address user needs effectively. This includes fixing reported issues, adding new features, and... 

In this thesis, we focus on some internal organization issues of the supply chain; in particular, we analyze some network design problems which are typical of producer companies. The aim is to optimize the flow of goods through the literature distribution network, from the plants where the goods are produced (supply points) to the demand points, which are essentially distributors such as wholesalers or retailers. The system addresses a class of distribution network design problems, which is characterized by multiple product families, a central manufacturing plant site, multiple central warehouses and distribution center, and retail outlets (customer zones) which demand multiple units of... 

The purpose of this research has been measuring how much studied companies use different levers of controls. Management control system has been described as the system which ensures the organization about implementing its strategy (Antony, 2004; Simons, 1995). In this research we chose Levers of Control framework (Simons, 1995) as the proper model to describe management control systems in organizations. Using related literatures, we developed a questionnaire to measure how much different organizations use each levers of control. The proposed questionnaire was distributed in three businesses with different Value Creation Logics (Stabell & Fjeldstad, 1998), to provide a ... 

Popular usage of composite materials in aerospace, civil and defense industries in the last decades has been the cause for paying more attention to optimization of composites tailoring. Due to inherent complexity of composite problems, i.e. discrete nature, complex interrelationship of design variables, existence of so many local optimum points, and etc., gradient base methods of optimization are found to be incapable and as a result using other powerful methods seems inevitable. Nowadays Genetic algorithm (GA) as an evolutionary technique is used for tackling composite problems. The success of a genetic algorithm can be quantified by estimating the cost, time required and the quality of... 

Nowadays, despite the special position of power electronic converters in the world, and the fact that they become an integral part of human life, still in the wake of a serious necessity the development process has not stopped and the increasingly fast pace, it opens up new horizons. This important necessity emerges from the environmental concerns regarding consumption of fossil fuels and their limited and imbalanced distribution which can be effectively addressed with the use renewable energy systems. By improving the quality of the semiconductor switches and offering new topologies in different functions as well as using new control methods, scholars try to develop enhanced converters in... 

With the progression of technology demands for novel method of heat cooling is increased so the old method of cooling such as heat removal by air stream with force convection and even single phase method was not sufficient for today’s industry need. Nowaday, spray cooling method which belongs to two phase cooling method is one of the most popular method. In this study two method of spray cooling: spray cooling with flow blurring nozzle and electrospray cooling were investigated. For both method, at first the physics of phenomena and morphology of spray is studied experimentally then the efficiency of heat removal in each method is evaluated by the assessment of variation of temperature and... 

Nowadays, concerns about the reduction of fossil fuels and environmental issues, have made renewable resources more important. Among these resources, photovoltaic (PV) systems are more popular than others, due to their environmental compatibility and unlimited availability of sunlight. Increasing the penetration level of PV systems in electricity networks presents various technical and control challenges such as voltage and frequency variations; and protection and harmonics issues. In this thesis, voltage rise problem due to reverse power flow in distribution feeders is discussed. This is one of the main obstacles to the expansion of these resources in distribution networks.Various solutions... 

Today, the correct management of construction projects in IRAN's water industry has become a severe concern for its managers. Construction projects of the water industry constitute a considerable part of the country's construction industry. Several significant Issues such as operation management, water industry projects, correct management of resources, crisis management in the water industry, increased productivity and useful life of structures, increasing productivity, and preventing water loss are among the determinative challenges in construction projects in Iran. One of the new methods for the correct management of the life cycle of projects in this area is the use of Building... 

The distinction between SOEs and private firms in access to loans is essential from the viewpoint of policy-making. This distinction is more crucial when we know that the difference is caused by factors other than natural market forces and has emerged merely by government ownership. In this paper, we investigate a unique intervention in privatization and identify the causal effect of government ownership on access to loans. In this respect, we study Sahamedalat in Iran by using DID approach and estimate the effect of giving up the treatment firm's cashflow right on the amount and composition of the loans. The results show the intervention significantly decreases the long-term loan of the... 

In this dissertation, we investigate the problem of the existence of finite geodetic sequences from point to point (0, n). This has not been proven in the general case. In this dissertation, we present an article that illustrates this question in a particular case of z ^ 2 subspaces whose self and complement are infinite and connected (e.g., slit planes, half-planes, and sectors). Writing x_n for the sequence of boundary vertices, we show that the sequence of geodesics from any point to x_n has an almost sure limit assuming only existence of finite geodesics. For all passage-time configurations, we show existence of a limiting Busemann function. Specializing to the case of the half-plane, we... 

This research attempts to develop the optimal solution for an inventory problem consisting of a single machine which produces items some of which may be defective. We assume that no shortages are allowed and all defective items are to be reworked. Setup cost for rework and waiting time of defectives are considered. This research consists of two different parts. In the first part we consider two different policies where in the first policy in each cycle after the regular production the machine is setup for the rework of defectives of the same cycle. In the second policy several cycles constitute a period. All the defectives produced in the period are reworked in the last cycle of that period....