Fault Tolerant Distributed Computing in Deep Neural Networks

, M.Sc. Thesis Sharif University of Technology Zare Ahangarkolaei, Mohammad (Author) ; Aref , Mohammad Reza (Supervisor) ; Maddah Ali, Mohammad Ali (Co-Supervisor)

Abstract

Nowadays, with the development of machine learning and deep learning on one hand, and the dramatic increase in the amount of information available and the complexity of models on the other hand, it is practically impossible to implement learning algorithms on a single node. Thus it is inevitable to distribute learning algorithms on several machines. In a distributed system, the main operations are divided into smaller tasks and performed by different nodes. The final result is then calculated by exchanging messages among the existing nodes.In this thesis, a method is introduced to compute the gradient of a massive data set in a distributed system. In this problem, there are a number of...

Optimal Design of Passive Control Systems Using Stiffness Modification and
Pole Assignment and Sliding Mode Control Algorithms

, M.Sc. Thesis Sharif University of Technology Zare, Ali Reza (Author) ; Ahmadizadeh, Mehdi (Supervisor)

Abstract

A methodology is developed for designing optimum passive energy dissipation systems using active control algorithms. A combination of stiffness reduction and increase of damping is utilized to reduce both acceleration and displacement response. In this method, first an active control system is designed using pole assignment and sliding mode control algorithm. Here, the methods to use the actives algorithms aremodified such that the resulting properties can be achieved by a passive control system using viscous fluid dampers. Next, a passive control system is designed to result in the structural properties close to those extracted from the actively controlled system. It is shown that this...

The Effect of Martensite Volume Fraction on Toughness of Triple-Phase Steels

, M.Sc. Thesis Sharif University of Technology Zare, Ahmad (Author) ; Ekrami, Ali Akbar (Supervisor)

Abstract

AISI 4340 steel bars were austenitized at 900°C for 1 hour followed by heating at 740°C (ferrite and austenite region) for 100 min and quenching into a salt bath at 300°C for different times followed by quenching into water to obtain triple phase microstructures with 34 Vol.% ferrite and various martensite (or bainite) contents. Presence of three phases in adjacent of each other confirmed by metallographic analysis and TEM technique. Volume fraction of different phases was measured by image analyser. The results of optical microscopy showed that by increasing VM, morphology of martensite varies from uniform distribution of small spherical network particles to large blocky islands with...

Seismic Performance Evaluation of HV Circuit Breakers in Transmission Substations and Application of Base Isolation to Improve their Behavior

, M.Sc. Thesis Sharif University of Technology Zare Feizabadi, Ali (Author) ; Bakhshi, Ali (Supervisor)

Abstract

The main goal of this study is to evaluate the seismic performance of HV circuit breakers of power substations and optimize their seismic behavior using base isolation systems. Iran is in a region with high seismicity and has experienced severe earthquakes in recent decades that have resulted in serious damages to critical infrastructures. These include power substations that are important during and even after an earthquake in providing electricity for homes, industries, amenities, emergency facilities, public transportation and more. The seismic performance of HV circuit breakers, which is an important equipment for power substations, has not been satisfactory in past earthquakes and has...

Security analysis and confidentiality in the Internet of Things

, M.Sc. Thesis Sharif University of Technology Zare Jousheghani, Zahra (Author) ; Aref, Mohammad Reza (Supervisor)

Abstract

Nowadays, Internet of Things is considered as a global infrastructure to establish communication between physical world and virtual world by using existing technologies. Its purpose is enabling things to establish communication with anything and any person in any time and any place by using existing networks and services. This technology makes different aspects of people's life smarter, facilitates doing works, and increases the quality of people's life. But, the development of Internet of Things faces to fundamental challenges that one of the most important of them is security and privacy preserving of users. According to the projects of European Research Cluster on the Internet of Things...

Synthesis of new Modified Composites Based on Nanoporous Materials and their Application in Environmental Pollutant Degradation

, M.Sc. Thesis Sharif University of Technology Zare Soheili, Hossein (Author) ; Gholami, Mohammad Reza (Supervisor)

Abstract

In this projekt, nanophotocatalysts containing metal oxides and oxy-acids based on the nanoporous materials were synthesized. The photocatalytic properties of the prepared samples were evaluated by the photodegradation of day moleculs in photocatalytic systems. The catalytic results revealed that Ag3VO4/Cu-MOF/rGO exhibits noticeably an improvement in both efficiency and rate of AB92 photodegradation in comparison with the pure Ag3VO4. Using different scanning mechanisms for the catalytic properties of the synthesized nanocomposites, it was clearly demonstrated that the anionic superoxide plays a decisive role. Reduction of 4-NP in the presence of NaBH4 was also used to investigate...

An Empirical Research on the Task-Induced Involvement Load Hypothesis: A Case for International Learning

, M.Sc. Thesis Sharif University of Technology Zare, Mousa (Author) ; Jahangard, ALi (Supervisor) ; Salehi, Mohammad (Co-Advisor)

Abstract

Laufer and Hulstijn (2001) proposed the Task-Induced Involvement Load Hypothesis stating that in the retention of new words in an incidental context, tasks with higher involvement load will be more effective than tasks with lower involvement load. The present study aimed to examine whether the retention of vocabulary is enhanced with an increase in the amount of task-induced involvement load in an intentional learning environment. Moreover, it was investigated whether proficiency level of learners had a role in the effectiveness of the vocabulary tasks with different involvement loads. Four groups of university students, male and female, participated in the study. They were given a TOEFL...

Feedback control of the neuro-musculoskeletal system in a forward dynamics simulation of stair locomotion [electronic resource]

, Article Proc. of IMechE Part H: Journal of Engineering in Medicine ; 2009, Vol. 223, No. 6, pp. 663-675 Journal of NeuroEngineering and Rehabilitation ; Volume 11, Issue 1, 30 April 2014, Article number 78 Selk Ghafari, A. (Ali) ; Meghdari, Ali ; Vossough, Gholam Reza ; Sharif University of Technology

Abstract

The aim of this study is to employ feedback control loops to provide a stable forward dynamics simulation of human movement under repeated position constraint conditions in the environment, particularly during stair climbing. A ten-degrees-of-freedom skeletal model containing 18 Hill-type musculotendon actuators per leg was employed to simulate the model in the sagittal plane. The postural tracking and obstacle avoidance were provided by the proportional—integral—derivative controller according to the modulation of the time rate change of the joint kinematics. The stability of the model was maintained by controlling the velocity of the body's centre of mass according to the desired centre of...

Resorcinol-Formaldehyde Xerogel for Analysis of Environmental Pollutant in Aqueous Sample

, M.Sc. Thesis Sharif University of Technology Zare, Maryam (Author) ; Bagheri, Habib (Supervisor) ; Es-haghi, Ali (Supervisor)

Abstract

In this study, a new resorcinol-formaldehyde xerogel was synthesized based on sol-gel technology and employed as a sorbent for micro solid phase extraction (µ-SPE) of BTEX and some selected pesticides from aqueous samples.
In the first part, a µ-SPE method in combined with headspace solvent microextraction (HS-SME) along with gas chromatography- mass spectrometry detection (GC–MS) was developed for the analysis of BTEX in aqueous samples. In our knowledge, this is for the first time that these two different extraction methods has been coupled to maximize the advantage of each extraction method. Influential parameters such as the peristaltic pump flow rate, extraction volume, extraction...

Developing an Applied Model for Energy Management in Dairy Production Industry

, M.Sc. Thesis Sharif University of Technology Bahmanpour khalesi, Ahmad Reza (Author) ; Mokhtar, Ali Reza (Supervisor) ; Miremadi, Ali Reza (Supervisor)

Abstract

Reviewing trends of energy consumption in the world reveals that sooner or later energy resources will be depleted. This concerning rate of consumption has brought about more greenhouse gases (GHG) emission influencing deleteriously on environment and climate. Human has continued energy consumption to maintain and improve the quality of his life through industrial production. Industry as a significant energy user owns considerable contribution to this consumption. Several attempts have been carried out to develop energy management systems in order to improve the energy efficiency of industrial sectors. Whilst they are comprehensive and could be applied to any sector, there is lack of...

Improving the Resiliency of Distribution Grids Owning Different Distributed Generation (DG) Resources by Optimal Switching Device Placement and Microgrids Formation

, M.Sc. Thesis Sharif University of Technology Zare Bahramabadi, Majid (Author) ; Abbaspour Tehrani Fard, Ali (Supervisor)

Abstract

In recent years, climate change due to greenhouse gases caused an increase in frequency and intensity of the natural disasters such as hurricanes, blizzards and floods. Moreover, it is anticipated that such events will increase in the future. As a result, power system decision makers are looking for methods to improve power system resiliency against such natural disasters with low occurrence probability and high impact. In this report, the distribution system resiliency has improved via placing remote control sectionalizing switches and micro grids formation during natural disasters. In this regard, the concept of resiliency and its characteristics along with the effect of remote control...

An Experimental Study of the Effects of Sweep Wing on the Boundary Layer of 2D Wing

, M.Sc. Thesis Sharif University of Technology Tabrizian, Arshia (Author) ; Soltani, Mohammad Reza (Supervisor) ; Davari, Ali Reza (Co-Advisor)

Abstract

The behavior of boundary layer under the effect of the sweep angle is considered. The measurements were performed by a pitot tube rake. Three models with various sweep angels at angles of attack -2, 0 and 2 degree were tested. Both tip and root of all wings were closed by flat plates in order to prevent the flow to roll-up. However the flow field on the wing was still three-dimensional because of the sweep angle. The velocity on the wing has two components; longitudinal and lateral. The cross flow emerges due to the non-equilibrium of pressure and centrifugal forces. The velocity profiles showed that the magnitude of cross flow was stronger near the leading edge of the wing. The cross flow...

Gaining Competitive Advantage through Marketing Strategies in Container Terminal: A Case Study on Shahid Rajaee Port in Iran

, M.Sc. Thesis Sharif University of Technology Cheraghi, Hossein (Author) ; Miremadi, Ali Reza (Supervisor)

Abstract

The competitiveness of a port convinced shipping lines and shippers with a significant basis in selecting a port. Port authorities and port operators can make use of the competitive advantage as a parameter for counter measures by grasping the advantages and disadvantages of the ports and be a prime factor of opportunities and threats of the ports. Ports have a significant role in today’s networked business environment. They are being regarded as hubs that are part of various logistic systems. The very essence of a seaport is to link maritime networks and land network. These networks for the port are means of analyzing its competitiveness. A port overall competitiveness is determined by it’s...

Energy Management in Energy Harvesting Wireless Sensor Nodes

, M.Sc. Thesis Sharif University of Technology Rohbani, Nezam (Author) ; Ejlali, Ali Reza (Supervisor)

Abstract

Wireless Sensor Networks have become widespread because of their flexibility, applicability and ability to precept data with high accuracy. However, the most limiting factor in their usage is the amount of available energy in nodes since energy depletion in a node means that it is dead, therefore many efforts have been done for optimum energy management in Wireless Sensor Networks. In many cases, the key solution to prolong the network lifetime is load balancing. In this way, all the nodes will die (approximately) together and the lifetime of network will be maximized. Load balancing can be implemented in all layers from physical layer to application. It should be noted that it is not always...

Experimental Investigation of Mechanical Behavior of Structural Concrete with Combination of Waste Glass and Silica Fume

, M.Sc. Thesis Sharif University of Technology Faghihi, Kamyar (Author) ; Khaloo, Ali Reza (Supervisor)

Abstract

Concrete is the second most structural material in the world. So attention and promotion of the concrete mix design with respect to variable issues and requirements, is very important. On the other hand, these days environment and its pollution has become very popular discussion. Waste-glass which is produced by human products is one of the environmental pollutants. In this thesis it replaces some aggregate in concrete and it can reduce the level of this material in the world. Also we study effects of silica-fume as cement replacement and properties enhancer in our concrete mix design and see how it can ...

Strengthening RC Slabs under Various Loads and Boundary Conditions Using FRP Composites

, M.Sc. Thesis Sharif University of Technology Saber, Mostafa (Author) ; Khaloo, Ali Reza (Supervisor)

Abstract

In recent decades the use of FRP materials for strengthening structures has been developed extensively, thanks to their high strength, sufficient stiffness, high durablity, and ease of use. A great deal of research has been conducted on strengthening reinforced concrete beams and columns with FRP composites. By contrast, not many researches are performed on slabs, especially two-way slabs. In these few researches, the loading and boundary conditions are limited to simplest ones. Therefore, in this thesis, the focus of attention is on strengthening reinforced concrete slabs under various loads and boundary conditions using FRP composites.
In this thesis, first, FRP composites and their...

Optimal Batch Production for a Single Machine System with Rework

, M.Sc. Thesis Sharif University of Technology Haji, Babak (Author) ; Haji, Ali Reza (Supervisor)

Abstract

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....

Improving the Reliability of Energy Harvesting Wireless Sensor Networks

, M.Sc. Thesis Sharif University of Technology Jalali, Fatemeh (Author) ; Ejlali , Ali Reza (Supervisor)

Abstract

Energy harvesters are used in today’s Wireless Sensor Networks (WSNs) to harvest the energy from the environment. One of the important advantages of the energy harvesting sensor networks over battery-operated sensor networks is that the use of the energy harvester prolongs the life time of the nodes, while a battery-operated node becomes useless once its energy runs out. Although an energy harvester can provide a supply source with a lifetime much greater than a battery, the amount of available energy for an energy harvesting system is a random variable and is not as predictable as the energy of a battery. This unpredictability may cause reliability problems. In order to solve the existing...

Response of Curved RC Shear Walls Under Cyclic Loading

, Ph.D. Dissertation Sharif University of Technology Abdoos, Hatef (Author) ; Khaloo, Ali Reza (Supervisor)

Abstract

Reinforced concrete (RC) shear walls with a curved cross-section are appealing structural elements to architects and engineers due to the aesthetic and structural advantages. Owing to the paucity of decent experimental research on curved RC shear walls (CRCSWs), the seismic response of these structural elements is essentially unknown. In that regard, this study includes research on a high-demanding type of structural element, which has found its application in North America, Europe, Asia, and to some extent in the Middle East with relatively no design specifications and laboratory research, structural analysis, and design methodology. Therefore, in order to provide an insight into the...

Selecting a Sustainable and Resilient Supplier in Cold Supply Chain Using Grey Multiple Criteria Decision Making Techniques

, M.Sc. Thesis Sharif University of Technology Farahmand, Mitra (Author) ; Hajji, Ali Reza (Supervisor)

Abstract

Supplier selection is a strategic decision that has a key impact on the success of the supply chain. Due to the nature of goods and storage conditions in the cold supply chain has a great impact on environmental pollution compared to other chains, and it also has the possibility of disrupting the chain due to the importance of temperature and time conditions. Currently, due to the spread of international pressures on the observance of environmental and social principles, the issue of choosing a sustainable supplier has been raised. Also, the expansion of supply chains has caused the challenges and risks faced by supply chains to expand and disrupt the chain, so the decision of supply chain...