Sharif Digital Repository

In this work, a high-order accurate gas kinetic scheme based on the compact finite-difference Boltzmann method (CFDBM) is developed and applied for simulating the compressible rarefied gas flows. Here, the Shakhov model of the Boltzmann equation is considered and the spatial derivative term in the resulting equation is discretized by using the fourth-order compact finite-difference method and the time integration is performed by using the third-order TVD Runge-Kutta method. A filtering procedure with three discontinuity-detecting sensors is applied and examined for the stabilization of the solution method especially for the problems involving the discontinuity regions such as the shock. The... 

It is generally observed that the textbooks employed in the classrooms play a crucial role in the process of teaching and learning a second/foreign language. As a result, a number of studies have been carried out to evaluate English Language Teaching (ELT) materials. Trying to contribute to this growing body of literature, the present study was conducted to evaluate the eight most popular global textbooks which are taught in Iranian ELT institutes in terms of their task types according to Nunan’s (1999) classification of the tasks. Nunan (1999) classified tasks into different groups according to the strategies underpinning them. He divided tasks into five major groups each one consisting... 

No-one likes being confined to a hospital bed. Children particularly can feel lonely, bored or frightened in these conditions. Hours feel like days, and they may not be able to fully comprehend why they are there. Among kids hospitalized because of distinct diseases, children with cancer have incomparable status and needs. They experience physical and mental problems caused by cancer and medications. Cancer treatment may cause distress which can lessen the effectiveness of the treatment. Utilizing social robots to interact with children in clinical environments has been verified to both diminish their distress level and enhance the effectiveness of the treatment process. To improve the... 

In this thesis, the purpose of the research was to develop a four-wheeled Mobile platform (Lower body) with three degrees of freedom for a humanoid robot upper body which is called RASA. RASA robot was designed and constructed for helping kids who have speech and hearing impairments. The objective was to develop a low-cost and affordable robot as compared to its international models to be used at home or school as a teacher assistant. RASA can help kids to learn signs as fast as possible due to the game-based and entertaining education system. The wheeled base platform consists of a new mechanism with 6 bar linkage for bending robot from the hip to about 60 degrees from a vertical position... 

The statistics show that around 5% of the world's population suffers from deafness. For these people, the most comprehensive way of communicating with the world around them is using sign language. These facts will clarify the need for review in design practices, especially in designing user interfaces, in order to make technology usable for people with disabilities. The present study wants to design a sign language-based user interface for the RASA robot. The goal is to enable the robot to interact with deaf users. In the first step, a cognitive architecture developed, to enable the robot to interact by sign language in specific working conditions. The second step was the implementation of a... 

Simultaneous Localization And Mapping (SLAM) is regarded as one of the most significant advances in robotics in recent decades. It enables robots to map their surrounding environments without the need for external equipment and simultaneously determine their position on this map. In the present study, this technique was implemented on Arash social robot to enable it to estimate its position in the environment with decent accuracy and potentially be able to automatically move towards the targets determined on the map using a path planning algorithm. At first, Arash robot mechanically was redesigned for this technique, and then the hardware and software needed to high-level and low-level... 

Nowadays children’s toys and educational stuff, have been enhanced by technology and they have found capabilities like intelligence. It is obvious that after the period of using smart devices such as phones and tablets, robots and smart robotic tools will be popular. On the other hand, children are willing to use such smart devices. Social robots are smart ones that interact with humans and are not necessarily humanoid. One of the social robots applications is for educational purposes. Many studies have shown that teaching by means of robots has good effects on learning. For example robots have been used for educating autistic children. Moreover, robots have been used for rehabilitation and... 

The purpose of this research is the design and fabrication of a mobile social robot for children with cancer. This robot is named Arash. Interaction with the robot can improve children's education, as well as their mental condition. Design and development of Arash robot project have been carried out in a number of M.Sc. projects. In the present study, it is specifically focused on three areas of activity:
1. Design and fabrication of the robot head (and the overall appearance of the robot)
2. Design and development of human-robot interactions
3. Social and educational interactions/interventions of the robot with children
In this study, with the cooperation of child... 

This thesis covers the design and realization steps of the upper-body of RASA, a social humanoid robot to be used as a Persian sign language (PSL) teaching assistant. In the design and fabrication processes, three main requirments is defined. First requirement is the robot's ability to perform PSL. The second one is for the robot to posess the characteristics required for a social robot interacting with targeted groups of people. And the third one is for the robot to be realized with minimum required cost. Further design guidelines are generated based on these three requirements. Analysing the structure of Persian sign language, the kinematic layout of the upper-body of the robot, regarding... 

This study investigated the effect of Robot Assisted Language Learning (RALL) on the vocabulary learning and retention as well as anxiety and attitude of Iranian English as Foreign Language (EFL) junior high school students in Tehran-Iran. After taking a vocabulary pretest, 46 beginner level female students at the age of 12, studying in their first year of junior-high participated in two groups of RALL (30 students) and non-RALL (16 students) in this study. The textbook used was the English book (Prospect-1) devised by the Iranian Ministry of Education for 7th graders, and the vocabulary taught and tested (pretest and posttest) were taken from this book. Moreover, the treatment given by a... 

The present case study investigates the effect of applying a humanoid robot as a teacher- assistant to teach a foreign language (English in this case) to Iranian children with autism. Two groups of three male high-functioning autistic students (6-10 years old) with little or no background in English participated in the current study. The humanoid robot NAO made by Aldebaran Robotics was used as a teacher assistant to teach English to the Robot Assisted Language Learning (RALL) group. The non-RALL group received the same lessons simply without the presence of the robot in teaching sessions. However, the non-RALL group also had the chance to interact with the robot through some robotic games... 

Although Robot Assisted Language Learning (RALL) has recently received attention as a tool for language learning, its role in pragmatic development has gone unnoticed. Hence, this study sought to explore the effect of RALL on pragmatic learning of greeting, thanking, and request speech acts by young Persian-speaking EFL learners. To this end, 38 preschool female and male kids (3-6 years old) were assigned to the RALL (19 students) and game-based (19 students) groups. The humanoid robot for the RALL group was used as an assistant to the teacher while for the game-based group the instruction was based on gaming methods such as command, mystery bag and pass the ball games. The instructional... 

In recent decades, the soil-structure effect has been considered in seismic studies. Most of these researches are based on the premise that the foundation is bonded to the ground. However, several examples of structures that experienced uplift have been reported. Uplift affects the soil-structure contribution and nonlinear behavior of the structure. It seems that a parametric study should be done for the simultaneous effects of the soil-structure interaction, foundation uplift and inelastic behavior of the superstructure. Although the most accurate methods to estimate the behavior of structures is the nonlinear time history analysis, this analysis is very time consuming. The endurance time... 

From the creation of the first robots, researchers have been fascinated by the possibility of interaction between a robot and its environment, by the possibility of robots interacting with each other and with humans. The common, underlying assumption is that humans prefer to interact with machines in the same way that they interact with other people. In this work, an assistant robot is developed based on a commercial platform, known as Alice R-50 (with the Iranian name of Mina). Alice is designed specifically for human-robot social interaction and has been used widely for studies on developmental and social robotics. It is used to improve and encourage the development of communication and... 

Natural intuitive human-robot interaction depends on how responsive a social robot can be to environmental information. Speaker localization is a prominent ability for communication and socialization that allows the robot to react to a speaker by turning its head towards it. In this paper, we have designed and implemented a robotic head, “Ava”, which turns toward the speaker in noisy environments. Ava is able to detect and enhance a speech activity and estimate the azimuth direction and vertical level of a speaker. The speech segments which are differentiated by a Speech Activity Detection system are processed to reduce noise levels. Then, by extracting the binaural features of two signals... 

Using social robots as Iranian sign language teaching assistants can be an important step in expanding communication with the deaf in the future. In the literature, it has been shown that user interfaces with adaptive behavior lead to more technological acceptance by the user and increase educational productivity compared to non-adaptive ones. This project aims to empower the RASA robot to perform adaptive Iranian sign language teaching to users, meaning that four of the robot’s outputs will be adaptive to the user: the word to teach, the performance speed, number of repeats, and the robot’s emotional reaction. The first important innovation of this research is the use of a Deep Neural... 

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... 

Social robots are a group of robots designed and built to interact with humans, so the ability to interact emotionally in these robots, especially in interaction with people with hearing and speech disorders, is essential because these people do not have an emotional state sound. Therefore, in this research, an emotional interaction system based on recognizing the user's emotional state from his facial state using deep learning algorithms as well as performing an appropriate emotional response on the robot's face has been designed and implemented on an expressive social robot. In order to design the emotional state recognition system, first, the best model was found on the large AffectNet...