Sharif Digital Repository

Over the past two decades, the production of ultra-light drones has increased dramatically. These aircraft are used in applications such as filming, surveying, etc. One of the most important goals is to fly them for a long time. From time immemorial, a lot of work has been done to get such birds to fly, but nothing has ever been done on their engines and propellers, and they have always been considered ideal models (in other words, their efficiency is a bit ideal). In this dissertation, the main purpose is to study some of these sets and to obtain the flight time of a particular drone. First, a low-velocity wind tunnel was built to examine these complexes, then we tested these complexes... 

One of the important questions in mathematics is generalized. In case of metric spaces, one of the questions is: Can we extend notions of Riemannian geometry to arbitrary metric spaces smoothly? Ricci curvature is one of the most important concepts in differential geometry. Ricci curvature is defined for the Riemannian manifold and has many applications in mathematics and physics like Einstein’s equation in relativity theory. There is a good notion for a metric space having “sectional curvature bounded below by K” or “sectional curvature bounded above by K”, due to Alexandrov. Can we define the concept of Ricci curvature in metric space? A motivation for this question comes from Gromov’s... 

Generally, nowadays, machine learning methods are used in many different areas for their superiority over other methods of prediction. Although being a tough task, stock market prediction with machine learning approaches is being spread due to satisfying results published ever yday. Machine learning methods usually use varied kinds of data ,including structured data such as market data, technical indicators and some fundamental data as well as unstructured one entailing text and graph data in order to enhance their predictability capacity. In this thesis we aimed to find out more about the importance and the contribution of structured data in prediction and we tried to attain a framework... 

Seismic design codes reduce loads by using response modification factor. Because of the reserved strength in structural elements and capacity of structure to dissipate energy, structures can be designed for lower seismic loads. This factor has modified over time. In this thesis, the effect of the reduction in behavior factor on the response of two kinds of reinforced concrete systems were evaluated. Moment resisting frames and dual systems with different heights and regularity in plan, heve been design according to the behavior factor which is recommended in the 3rd edition of the Iranian codes of practice for seismic resistance design of buildings (Standard No. 2800). Drift and... 

This thesis presents an inventory control system which is based on Meta-heuristic Algorithms.In this thesis we will optimize the input values of our tree-echelon inventory model (keeping costs,stock worth,reorder costs,...) with these Algorithms. The presented method is able to determine the optimal stock level, costs of system and number of shipments in the system. The method is basically a decision support system (DES) and it is able to provide the order scheduling parameters of goods at operational level. The aim of the current research is to demonstrate that a Meta-heuristic algorithmis capable of solving complex inventory problems and with future improvements it is able to achieve... 

The current design procedure known as Force-Based Design (FBD) method, generally, does not lead to uniform distribution of drift, hysteretic energy, and ductility demands (or structural damage) along the height of the moment frames under strong earthquakes and these performance parameters can be much higher and concentrate damage on one or more of the lower structural stories. This paper presents an iterative wave propagation (WP) based technique to calculate the seismic nonlinear response of multistory buildings as an extension of the layered soil media, founded on bedrock and subjected to vertically propagating shear waves, which leads to the introduction of a new Lateral Load Pattern... 

This project aims to design a novel structure that can inhibit the activitvation of the c-Met enzyme using amino acids and sugars building blocks. The c-Met enzyme is a receptor tyrosine kinase that plays a significant role in several biological activities such as cell proliferation, survival, and invasion. Abnormal activity of the enzyme is linked to the progression of various types of cancer, including breast, lung, liver, and stomach cancer. The proposed sugar amino acid conjugate structures is expected to increase stability amino acids and dipeptides in the physiological environment, improve membrane permeability via active transport mechanism, and reduce toxicity and side effects by... 

The purpose of this experimental study is to obtain 3 proper 3D-Printable concrete mix designs including high-strength concrete, EPS concrete with volume ratio of 25% and carbon fiber reinforced concrete with volume ratio of 1%. After successfully reaching above mix designs, 4 concrete beam samples were 3D-Printed of which 3 of them made according to the mix designs and one using the latter 2 designs as composite section. Putting the beam samples under 4-Point Bending Test, Results show a significant improvement in the performance of the composite section  

Concrete-filled FRP tubes have gained popularity among structures in areas with harsh environmental condition. Despite their unique material properties such as resistance to corrosion, noticeable axial stiffness, and durability, FRP materials have poor resistance to elevated temperatures. This paper presents numerical investigations on the behavior and capacity of concrete-filled pultruded GFRP tubes (CFGFTs) after exposure to elevated temperatures under concentric compression. Variables in this study were the tube’s thickness of 3, 5, and 7mm, the infill concrete’s compressive strengths of 30 and 60MPa, and the exposure temperature of 25, 100, 200, 300, and 400°C. The results in this study... 

In this research, a new method is proposed for constructing concrete structures with complex geometry, including topology-optimized concrete dams on a small scale. According to global statistics, concrete is the most consumed material in the world after water, and its production process causes a lot of damage to the environment. One of the best ways to reduce concrete consumption is to use tools such as topology optimization to design concrete structures. Nevertheless, few research has been done in the field of topology optimization of concrete dams, one of the important reasons for which is the difficulty of building physical model to perform physical tests, validating numerical models, and... 

Geographical environments can be modeled through the medium of TINs, in which some discrete points are sampled as vertices, and the union of polygonal faces, particularly triangles, constitutes its surface. As regards the two-dimensional space, the TIN boundary is an x-monotone path and we focus on this case. If the number of vertices is too large to be stored or some sampled points should be removed due to a lack of vital information, the necessity of TIN simplification arises. On top of this situation, if a point observer locates on or above the TIN, the points visible to the observer have more priorities to be considered in the simplified TIN. For example, human eyes can see the closer or... 

Vimseltinib, a small molecule inhibitor, represents a promising avenue for combating cancers linked to macrophage-associated processes through its targeted action on the CSF1R tyrosine kinase receptor. CSF1R, a pivotal member of the tyrosine kinase receptor family, plays a crucial role in macrophage differentiation and function. This protein's significance is underscored in conditions such as tenosynovial giant cell tumors (TGCTs) and the presence of tumor-associated macrophages, wherein overproduction of CSF1 by neoplastic cells recruits CSF1R-dependent immune cells, fostering tumor expansion. The intricate interplay extends to tumor-associated macrophages, particularly the M2 subtype,... 

This research investigates the impact of a new type of latex called Carboxylated Styrene Butadiene Rubber (XSBR) on the mechanical properties and permeability of latex-modified concrete. Latex-modified concretes offer numerous advantages, but a key challenge is the reduction in compressive strength, hindering their widespread use, especially in structural applications. In the initial phase of this study, the influence of XSBR latex is examined, and four different dosages of XSBR latex are incorporated into concrete. Keeping other parameters constant, especially the water-to-cement ratio, a comparison is made between different mix designs. All specimens are subjected to two different curing... 

Meaningful gesture recognition, whose purpose is to interpret human movements, plays a crucial role in various fields such as human and computer interaction, sign language recognition, robot control, and medical applications. Sign language recognition is regarded as the most significant use of gesture recognition by many researchers. Sign languages are the natural medium of communication for millions of deaf people all over the world, and the existence of a sign language recognition system has significantly aided in facilitating communication between deaf individuals and others. Despite numerous studies conducted in this field in recent years, there are still many challenges to continuous... 

In addition to being their primary means of communication with the people around them, sign language for deaf children plays a significant role in shaping their intellectual and cognitive development. Research has shown that the use of robots in education has a substantial impact on the learning process of the learner. As the teaching process requires long-term interaction with different users, the use of adaptable techniques enables the creation of a social robot capable of productive interaction with users of varying performance levels. One of the objectives of this research is to use continual learning algorithms to enhance adaptability in the teaching process. Another goal is to design... 

Persistent homology is one of the main tools in Topological Data Analysis. Indeed, to deal with a huge dataset while noise sensitivity is important, persistent homology can reflect some information about data in the form of persistent homology groups and persistence diagrams. Note that statistical or linear algebraic tools are not suitable to work with huge datasets with very high dimensions. In this thesis, we discuss the concept of persistent homology and investigate some of its properties such as the stability of the persistence diagrams. Indeed, persistence diagrams are obtained from the generating sets of the persistent homology groups. Further, we discuss an application of persistent... 

Despite the significant progress of machine learning models in the health domain, current advanced methods usually produce non-transparent and black-box models, and for this reason, they are not widely used in medical decision-making. To address the issue of non-transparency in black-box models, interpretable machine learning models have been developed. In the health domain, counterfactual scenarios can provide personalized explanations for predictions and suggest necessary changes to transition from an undesirable outcome class to a desirable one for physicians. The aim of this study is to present an interpretable machine learning framework in the health domain that, in addition to having... 

In this MSc. thesis a dongle and gateway are designed and developed for outdoor applications. In addition, a mesh networking protocol is developed for these dongle and gateway that does not impose the deficiencies of the other available protocols in the literature. The developed dongle supports a Lora LPWAN module, which is very popular in IIOT applications. It also supports the ESP32 module, which is a very popular IIoT module in the WiFi family. The developed dongle supports one-wire temperature and humidity sensor, analog and digital sensors, CAN and RS485 data communication protocols and it is able to produce on/off outputs. The developed gateway supports LAN and 4G protocols in order to...