Sharif Digital Repository

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... 

Decades ago, scientists and researchers found out proteins are not function isolated and act in multi protein complexes as complex networks. So, they started to study about proteins and their interaction in the term of protein-protein interaction, therefore, the number of publication in this field grows rapidly. This large amount of published articles (in scientific journals or web pages or books) are unstructured and it is hard to classify them manually. Also, study and read all of these documents is difficult for one person. Hence, it’s better to find a way which could help scientists and researcher to study these unstructured or semi-structured information more easily. The best way to... 

Nowadays, Machine learning algorithms are used to perform different tasks. Due to the high computational complexity of machine learning methods especially deep learning methods, running these methods efficiently on resource-constrained applications such as the Internet of Things (IoT) is challenging. To address the mentioned limitation, many devices send the raw data to the edge or cloud for classification due to limited computational power. This brings security and privacy issues and increases computational latency and network traffic. Hardware accelerators can be used to overcome this challenge by improving the computational power of the end nodes. Power and energy consumption with... 

In recent years, social robots have used simple and complicated context-aware systems to provide better services for users. The navigation module is one of the most important modules in which a context-aware system can be used; Where a social robot can change the way it navigates with respect to the context that the users are experiencing in a manner that fits the cultural background of the users. This kind of navigation helps the robot to keep its users safe both psychologically and physically. In this research, we present a context-aware navigation method that changes its proxemics due to the group context the users are experiencing. This research consists of three main parts: first, a... 

In recent years with the development of industrial automation, artificial intelligence, and the coming of the fourth-generation industrial revolution, making robots intelligent and solving old challenges in non-linear systems in order to make human life easier has always been the point of view of researchers. Flight systems are always considered to be one of the most nonlinear systems. In linear systems, a PID controller can be easily designed and implemented; But in non-linear systems, because the set point is constantly changing, the PID gain must be manually adjusted by the operator, which is almost impossible in practice; Therefore, finding a fast and efficient way to solve this... 

The hand is an important part of the human body, the loss of all or part of it greatly reduces a person's ability to perform daily tasks. For people who have lost this significant organ, replacing it with an artificial limb that can meet some of their needs is essential. Today, all robotic prostheses use electromyographic (EMG) signals from the remaining muscles of the disabled limb as input signals. Classifying the EMG signal and converting it to a control signal faces serious challenges. Variation of signal properties over time, electrode slippage, muscle fatigue, changes in muscle contraction intensity, and changes in limb position and direction are some of these challenges. Therefore, a... 

Sign language is an essential means of communication for millions of people around the world and serves as their primary language. However, most communication tools and technologies are designed for spoken and written languages, which can create barriers and limitations for the deaf community. By creating a sign language recognition system, we can bridge this communication gap and enable people who use sign language as their primary mode of expression to communicate better with people and their surroundings. This sign language recognition system increases the quality of education, the quality of health services, improves public interactions and creates equal opportunities for the deaf... 

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... 

Nowadays, one of the challenges in social robotics is to navigate the robot in social environments with moving elements such as humans. The purpose of this study is to navigate the Arash 2 social robot in a dynamic environment autonomously without encountering moving obstacles (humans). The Arash 2 robot was first simulated in the Gazebo simulator environment in this research. The simultaneous location and mapping (SLAM) technique was implemented on the robot using a lidar sensor to obtain an environment map. Then, using the deep reinforcement learning approach, the neural network developed in the simulation environment was trained and implemented on the robot in the real environment. The... 

Moving towards a sustainable energy system in the evolving society requires the utilization of new applications like Electrical Vehicles (EVs) and integration of Renewable Energy Sources (RESs) which will make new challenges for today’s power grids. To address these challenges, it is essential for emerging demand control paradigm to not only adapt the required demand with available supply but also consider the comfort and the level of lifestyle each customer may have in practice. In this research, due to the ever-growing interconnectivity of the grids, a distributed Commodity Market (CM) framework is proposed in which intelligent agents embedded in Demand Control Entity (DCE) units in... 

The usage of robots as our friends has been proliferated these days. Knowing that they are going to be used in ordinary houses, we should develop methods and algorithms in order to provide a situation for end-users to program their own robots for their desired tasks. Learning from Demonstrations (LfD) can play a crucial role in this field. In this study, we had taught a non-verbal communication method (pointing) to a robot utilizing LfD. The learning method used was TP-GMM1. The rationale to use this method was that it models all the degrees of freedom together, and we thought it might be an essential parameter to make a movement more natural and understandable which could be two vital... 

Using learning from demonstration approaches is one of the ways to teach a robot how to perform different skills. In classic methods of learning from demonstration, the subject should wear some sensors and devices which is and expensive way. But, with the progresses that have been made in the context of computer vision, it is possible now to achieve to the same results with less cost. Learning from observation is the approach that would be used in this project to do that. By using this method, when robot watches a video, it tries to understand the behavior of the subject and behave in the same way.The purpose of the project is that the robot learns some social (interactive) skills through... 

Autism is a neurodevelopmental disorder for which there is no definitive cure and it is increasing every year for people with this disorder. In the last decade, the use of virtual environment to improve the skills of people on the autism spectrum has increased. In this research, a semi-intelligent algorithm was designed for a virtual reality game that could provide a more appropriate step to the user according to the user's responses. Our focus is on designing games to strengthen the child in terms of shared attention and eye contact. In other words, we seek to create a virtual environment with the ability to intelligently adapt to interact with our user and turn it into a suitable coaching... 

Environmental flows are seldom independent of plants impact. Aquatic canopies are mostly submerged and flexible; this causes a significant impact on Hydrodynamics of flow and mixing structure. Experimental and analytical investigation of vertical mixing in vegetation canopies with flexible submerged vegetation is the aim of this study. Most of the previous studies on flexible submerged vegetation were conducted to study the transverse and longitudinal mixing. In this study, flexible submerged vegetation in the density range of 2.8% to 4.2% was used to study the vertical mixing.The concentration profiles at four separate stations were obtained by image processing. The results for the... 

The complexity of today's world has led us to the point where we will have problems in the intellectual and practical fields without relying on the testimony of experts. Maybe if we could measure the validity of the information by our own knowledge, we would definitely choose this option. But social life has made us rely on others to get the beliefs we need. We consider most of the beliefs we acquire in school, universities, in science books, news, debates and television documentaries to be examples of knowledge. We also claim to know a set of beliefs presented to us by experts. We consider experts as reliable people and we rely on them. In the meantime, we know that we have no other reason... 

Employing social robots in interactions with children for educational and healthcare objectives could enhance the efficiency of interventions and boost the children’s cognitive and affective outcomes by increasing engagement and providing motivation. This dissertation investigates three main subtopics to determine the efficacy of utilizing social robots in speech therapy sessions in interactions with children suffering from speech and language disorders. We hypothesize that interacting with social robots acting as therapists’ assistants in speech therapy interventions contributes to the formation of language-based communications and improves the individuals’ language skills. The first... 

In this research, some inhibitors based on quaternary monoammonium salts and quaternary diammonium salts containing different anions were synthesized to prevent formation of methane gas hydrates, and they were characterized using 1H and 13C NMR spectra, IR spectroscopy, elemental analysis and mass spectrometry. Then, the synthesized compounds were used in an autoclave under 128 bar pressure under controlled isothermal conditions to determine retention time considering displacement amount of the gas hydrate temperature- pressure chart and also to determine subcooling of the samples using HW Hydrate software. According to the results T3, T4 and TBAHF compounds in their pure form, not only... 

Exact Renormalization Equations (ERGE) are powerful non-perturbative tools to study the dynamics of Quantum Field theories, with respect to the change of energy. Putting cut-off on momentums of the system, is the specific regularization that is used to obtain ERGEs. This regularization breaks the gauge symmetry in the case of gauge theories. So the symmetry will be lost through the energy flow as well.Finding a gauge symmetry for a regularized system is the aim of this research. Also we have investigated the related ERGEs and the behavior of symmetry through the flow  

Using flapping motions, birds produce aerodynamic forces required to fly. Flapping wing aerodynamics is one of the most complicated problems in unsteady aerodynamic field. Experimental study on the structure, the way of production and growth and the feasibility of controlling the leading edge vortex are the main goals of this research in order to improve the aerodynamic performance of flapping wings. Since leading edge vortex structure appears in both upstroke and downstroke of a complete storke in flapping motion, controlling the structure in one of the half-storkes can provide the possibility of having a better aerodynamic performance. In this research, the wing is designed and... 

In this thesis, the thermal and thermoelectric properties of graphene-based nanostructures are numerically investigated. The transport parameters, including Seebeck coefficient, electrical conductance, and thermal conductance are obtained as well as the thermoelectric figure of merit. The Hamiltonian matrix is set up using a third nearestneighbor atomistic tight-binding approximation and the dynamical matrix using a 4th nearest neighbor force constant approximation. Both ballistic and diffusive regimes are considered in this work. For transport investigation, the Landauer formula and the nonequilibrium Green’s function techniques are used. The role of temperature, geometrical parameters,...