Gait analysis of a six-legged walking robot using fuzzy reward reinforcement learning

, Article 13th Iranian Conference on Fuzzy Systems, IFSC 2013 ; August , 2013 , Page(s): 1 - 4 ; ISBN: 9781479912278 Shahriari, M ; Khayyat, A. A ; Sharif University of Technology

IEEE Computer Society 2013

Abstract

Free gait becomes necessary in walking robots when they come to walk over discontinuous terrain or face some difficulties in walking. A basic gait generation strategy is presented here using reinforcement learning and fuzzy reward approach. A six-legged (hexapod) robot is implemented using Q-learning algorithm. The learning ability of walking in a hexapod robot is explored considering only the ability of moving its legs and using a fuzzy rewarding system telling whether and how it is moving forward. Results show that the hexapod robot learns to walk using the presented approach properly

Analytical modeling of a Minimally Invasive Surgery grasper actuated by shape memory alloy wires

, Article International Conference on Robotics and Mechatronics, ICRoM 2013 ; Feb , 2013 , Pages 147-151 ; 9781467358118 (ISBN) Shahriari, M ; Zabihollah, A ; Sharif University of Technology

2013

Abstract

Minimally Invasive Surgery (MIS) is getting common these days. MIS robots using special tools can perform surgery precisely as humans. This is only possible with dexterous end-effectors and a well-controlled system. Local, lightweight and powerful actuators positioned at end-effectors provide the ability to decrease the degrees of freedom and simplify the design. This paper discusses a grasper design actuated by Shape Memory Alloy (SMA) wires that can be used in MIS robotics. The properties of a commercially available shape memory alloy are explored and analytical formulations for the actuation procedure are developed. The grasper actuated by SMA wires is studied and the procedure of...

Discrete formulation for two-dimensional multigroup neutron diffusion equations

, Article Annals of Nuclear Energy ; Volume 31, Issue 3 , 2004 , Pages 231-253 ; 03064549 (ISSN) Vosoughi, N ; Salehi, A. A ; Shahriari, M ; Sharif University of Technology

2004

Abstract

The objective of this paper is to introduce a new numerical method for neutronic calculation in a reactor core. This method can produce the final finite form of the neutron diffusion equation by classifying the neutronic variables and using two kinds of cell complexes without starting from the conventional differential form of the neutron diffusion equation. The method with linear interpolation produces the same convergence as the linear continuous finite element method. The quadratic interpolation is proven; the convergence order depends on the shape of the dual cell. The maximum convergence order is achieved by choosing the dual cell based on two Gauss' points. The accuracy of the method...

Modular framework kinematic and fuzzy reward reinforcement learning analysis of a radially symmetric six-legged robot

, Article Life Science Journal ; Volume 10, Issue SUPPL 8 , 2013 , Pages 120-129 ; 10978135 (ISSN) Shahriari, M ; Osguie, K. G ; Khayyat, A. A. A ; Sharif University of Technology

2013

Abstract

Hexapod robots gives us the ability to study walking robots without facing problems such as stability in many aspects. It has a great deal of flexibility in movement even if a leg becomes malfunctioned. Radially symmetric (hexagonal) hexapods have more flexibility in movement than rectangular leg alignments. Because of symmetry they can move in any direction and time efficiently. Inverse kinematic problem of this kind of hexapods is solved through a modular mobile view considering six degrees of freedom for the trunk. Then typical tripod and wave gaits are analyzed and simulated through the presented formulation. In Reinforcement Learning algorithm for walking it is important how to make...

Direct Discrete Method (DDM) and its application to neutron transport problems

, Article Scientia Iranica ; Volume 14, Issue 1 , 2007 , Pages 78-85 ; 10263098 (ISSN) Vosoughi, N ; Salehi, A. A ; Shahriari, M ; Heshmatzadeh, M ; Sharif University of Technology

Sharif University of Technology 2007

Abstract

The objective of this paper is to introduce a new direct method for neutronic calculations. This method, called Direct Discrete Method (DDM), is simpler than the Neutron Transport Equation and more compatible with the physical meanings of the problem. The method, based on the physics of the problem, initially-runs through meshing of the desired geometry. Next, the balance equation for each mesh interval is written. Considering the connection between the mesh intervals, the final discrete equation series are directly obtained without the need to first pass through the set-up of the neutron transport differential equation. In this paper, a single and multigroup neutron transport discrete...

γ' Precipitate dissolution during heat treatment of nimonic 115 superalloy

, Article Materials and Manufacturing Processes ; Volume 24, Issue 5 , 2009 , Pages 559-563 ; 10426914 (ISSN) Shahriari, D ; Sadeghi, M. H ; Akbarzadeh, A ; Sharif University of Technology

2009

Abstract

In precipitation hardenable materials, it is desirable to determine the precipitate dissolution temperature for homogenizing the microstructure by controlling the size and distribution of the precipitates. In this research, differential thermal analysis, dilatometry technique, heat treatments followed by microstructure evaluation were used to determine the -γ' dissolution temperature of Nimonic 115. It is assumed that the variation of enthalpy is governed by the changes in y volume fraction and γ concentration with time and temperature, and any contribution of the coarsening of γ' is neglected. The values obtained for the solvus temperature of γ precipitates by the three methods are all in...

The application of proportional hazards and frailty models to multistage processes surveillance

, Article International Journal of Advanced Manufacturing Technology ; Volume 74, Issue 1-4 , September , 2014 , Pages 461-470 ; ISSN: 02683768 Asadzadeh, S ; Aghaie, A ; Shahriari, H ; Niaki, S. T. A ; Sharif University of Technology

2014

Abstract

Monitoring industrial and service processes with the purpose of improving the product reliability has been largely addressed in the literature. The surveillance procedures have been proposed with the concentration on single-stage processes with independent quality characteristics. However, the cascade property in multistage processes entails specific monitoring methods which take into account the dependency structure among quality variables in successive stages of a process. This is referred to as regression-adjustment that justifies the heterogeneity in the study population and thus leads to optimal monitoring of multistage processes. In general, it is not straightforward to adjust a...

Tribological characterization of electroless Ni-10% P coatings at elevated test temperature under dry conditions

, Article International Journal of Advanced Manufacturing Technology ; Volume 62, Issue 9-12 , October , 2012 , Pages 1063-1070 ; 02683768 (ISSN) Masoumi, F ; Ghasemi, H. R ; Ziaei, A. A ; Shahriari, D ; Sharif University of Technology

Springer 2012

Abstract

An experimental study of wear characteristics of electroless Ni-10% P coating sliding against hard AISI 52100 steel pin is investigated. Experiments are carried out at room and 550°C temperatures. Heat treatment effects on tribological behavior of this coating are studied. The wear surface and the microstructure of the coatings are analyzed using optical microscopy, scanning electron microscopy, energy dispersion analysis X-ray, and microhardness testing equipment. It is observed that the forming of continuous oxide film on contacting surfaces of pin and disk improves wear resistance and decreases friction coefficient of the Ni-10% P coating. The results indicate that the wear resistance of...

Experimental study and mathematical modeling of partitioning of β-amylase and amyloglucosidase in PEG-salt aqueous two-phase systems

, Article Journal of Chemical and Engineering Data ; Volume 55, Issue 11 , 2010 , Pages 4968-4975 ; 00219568 (ISSN) Shahriari, S ; Vossoughi, M ; Taghikhani, V ; Safekordi, A. A ; Alemzadeh, I ; Sharif University of Technology

2010

Abstract

In this study, the partitioning of β-amylase in aqueous two-phase systems (ATPS) containing polyethylene glycol (PEG) with a molar mass of 6000 and 10 000 and KH 2PO 4 at T = (301.65 and 304.65) K was experimentally studied. In addition, the partitioning of amyloglucosidase in ATPS containing polyethylene glycol with molar mass of 4000, 6000, and 10 000 in the presence of Na 2SO 4 at T = (301.65 and 305.65) K was investigated. The effects of molar mass of PEG, temperature, mass fractions of salt, and the length of the tie line on partition coefficients of the enzymes were also studied. The experimental results showed that while the partition coefficients of enzymes decrease with increasing...

The influence of heat treatment and hot deformation conditions on γ′ precipitate dissolution of Nimonic 115 superalloy

, Article International Journal of Advanced Manufacturing Technology ; Volume 45, Issue 9-10 , 2009 , Pages 841-850 ; 02683768 (ISSN) Shahriari, D ; Sadeghi, M. H ; Akbarzadeh, A ; Cheraghzadeh, M ; Sharif University of Technology

2009

Abstract

In precipitation hardenable materials, it is desirable to determine the precipitate dissolution temperature for homogenizing the microstructure by controlling the size and distribution of the precipitates. In this research, the influence of various heat treatment and hot deformation conditions on the kinetics of γ ′ dissolution and its morphological evolution in Nimonic 115 was studied. In addition, hot deformation behavior of the material was investigated using hot compression experiments at varying temperature (between 1,050°C and 1,175°C) and strain rates (between 0.01 and 1 s-1) up to a true strain of 0.8. The values obtained for the solvus temperature of γ ′ precipitates by two methods...

Vorticity-Bases Adaptive Mesh Refinement for Upscaling of Highly Heterogeneous Porous Media

, M.Sc. Thesis Sharif University of Technology Shahriari, Arjang (Author) ; Firoozabadi, Bahar (Supervisor)

Abstract

The results of numerical simulation of underground flows are greatly affected not only by the discretization method of flow equations, but also by the way that the geological domain is upscaled. Including the detailed knowledge of heterogeneous permeability distribution is mostly neither feasible nor computationally efficient. So it is important to develop efficient grid generation and upscaling methods to simplify the fine-scale flow model while still including the impact of the heterogeneities as far as possible. Thus regions where parameters of interest have larger values or higher changes require finer grid blocks and regions with lower values or minor changes should have coarser grid...

Consequence Modelling of Ethylene Oxide Reactor of Morvarid Petrochemical Co

, M.Sc. Thesis Sharif University of Technology Shahriari, Esmaeel (Author) ; Rashtchian, Davood (Supervisor)

Abstract

As Ethylene Oxide is a highly toxic, flammable, and hazardous material, the consequences of any malfunction in an Ethylene Oxide reactor may be irreparable. The aim of this thesis is to evaluate the probable consequences of an accident in Morvarid Petrochemical Co.’s Ethylene Oxide Reactor in order to find probable hazardous scenarios. In this project, probable accidents were modelled and evaluated by Phast software in different scenarios, and the outcomes were investigated. In addition, if necessary, a set of solutions were proposed to decrease casualties in hazardous scenarios. The results may be used to change layouts according to Consequence Modelling. Results illustrated that...

Control of Three-phase UPS with Nonlinear Load Using Disturbance Observer Considering Transformer Concerns

, M.Sc. Thesis Sharif University of Technology Shahriari, Zohair (Author) ; Tahami, Farzad (Supervisor)

Abstract

Nowadays, non-linear loads comprise an important part of electrical grids. One of the most essential sources of nonlinear loads is switching power supplies, which mainly include power electronic rectifiers. When power outage occurs, Uninterruptible Power Supplies (UPS) must be able to supply these loads. The nonlinearity of the load has a significant effect on the Total Harmonic Distortion (THD) of the output voltage, which may not be easily reduced, especially in three-phase inverters. Furthermore, the presence of isolating transformers in these power supplies limits the control of harmonics and intensifies the nonlinear effects of the system.In this Master Thesis, a disturbance observer is...

Constructive Mathematics and Quantum Mechanics

, M.Sc. Thesis Sharif University of Technology Shahriari, Mohsen (Author) ; Ardeshir, Mohammad (Supervisor)

Abstract

In constructive mathematics, one has to construct a mathematical object in order to show that it exists. Consequently, some of classical theorems are not acceptable from a constructive point of view. In particular, the constructive validity of the parts of mathematics that play a role in forming physical theories is of interest. Here, we want to examine the constructive provability of some theorems related to quantum mechanics

Improving reliability in multistage processes with autocorrelated observations

, Article Quality Technology and Quantitative Management ; Volume 12, Issue 2 , 2015 , Pages 143-157 ; 16843703 (ISSN) Asadzadeh, S ; Aghaie, A ; Shahriari, H ; Akhavan Niaki, S. T ; Sharif University of Technology

2015

Abstract

Multistage process surveillance is considered to effectively improve the product reliability in manufacturing or service operations. To this end, the process output is commonly inspected under specific conditions and the values of the reliability-related quality characteristic are measured. However, in some cases, the observations from the process output are autocorrelated. This brings about the situation where the use of existing monitoring schemes is futile. Therefore, a class of survival analysis regression models called the proportional hazards (PH) model has been modified to justify the effect of cascade property in line with the autocorrelation issue. Subsequently, three monitoring...

Vulnerability take grant (VTG): an efficient approach to analyze network vulnerabilities

, Article Computers and Security ; Volume 26, Issue 5 , 2007 , Pages 349-360 ; 01674048 (ISSN) Shahriari, H. R ; Jalili, R ; Sharif University of Technology

2007

Abstract

Modeling and analyzing information system vulnerabilities help predict possible attacks to computer networks using vulnerabilities information and the network configuration. In this paper, we propose a comprehensive approach to analyze network vulnerabilities in order to answer the safety problem focusing on vulnerabilities. The approach which is called Vulnerability Take Grant (VTG) is a graph-based model consists of subject/objects as nodes and rights/relations as edges to represent the system protection state. Each node may have properties including single vulnerabilities such as buffer overflow. We use the new concept of vulnerability rewriting rule to specify the requirements and...

Using CSP to model and analyze transmission control protocol vulnerabilities within the broadcast network

, Article Proceedings - 2004 International Networking and Communication Conference, INCC 2004, Lahore, 11 June 2004 through 13 June 2004 ; 2004 , Pages 42-47 ; 0780383257 (ISBN) Shahriari, H. R ; Jalili, R ; Sharif University of Technology

2004

Abstract

Spreading networks and increasing their complexity has complicated the task of security analysis. Accordingly, automatic verification approaches have received more attention recently. In this paper, we modeled a network including a set of hosts (clients and servers) using the process algebra CSP in order to verify the Transmission Control Protocol (TCP) behavior against an active intruder. The model is verified using the FDR tool and as a result, some attack scenarios violating the security are found. The scenarios showes how an intruder can compromise the server trust to its clients. As the model is modular, extendable, and scalable, more complex attack scenarios (combination of simple...

Modeling of network security-related behaviours using NVML

, Article 8th International Multitopic Conference, INMIC 2004, 24 December 2004 through 26 December 2004 ; 2004 , Pages 506-511 ; 0780386809 (ISBN); 9780780386808 (ISBN) Shahriari, H. R ; Jalili, R ; Sharif University of Technology

Institute of Electrical and Electronics Engineers Inc 2004

Abstract

Nowadays, security has become an important issue for organizations especially in e-commerce applications. The spreading of networks and increasing of their complexity has complicated the task of security analysis, therefore automatic approaches have received more attention recently. This paper proposes a model-based approach to analyze the overall security of a network, based on the interaction of hosts within the network. A simple language is introduced far modeling securityrelated behaviours of networks and systems. Using the language, a case study is described and its formal model and security properties are presented. © 2004 IEEE

Vulnerability analysis of networks to detect multiphase attacks using the actor-based language Rebeca

, Article Computers and Electrical Engineering ; Volume 36, Issue 5 , 2010 , Pages 874-885 ; 00457906 (ISSN) Shahriari, H. R ; Makarem, M. S ; Sirjani, M ; Jalili, R ; Movaghar, A ; Sharif University of Technology

2010

Abstract

Increasing use of networks and their complexity make the task of security analysis more and more complicated. Accordingly, automatic verification approaches have received more attention recently. In this paper, we investigate applying of an actor-based language based on reactive objects for analyzing a network environment communicating via Transport Protocol Layer (TCP). The formal foundation of the language and available tools for model checking provide us with formal verification support. Having the model of a typical network including client and server, we show how an attacker may combine simple attacks to construct a complex multiphase attack. We use Rebeca language to model the network...

Network vulnerability analysis through vulnerability take-grant model (VTG)

, Article 7th International Conference on Information and Communications Security, ICICS 2005, Beijing, 10 December 2005 through 13 December 2005 ; Volume 3783 LNCS , 2005 , Pages 256-268 ; 03029743 (ISSN); 3540309349 (ISBN); 9783540309345 (ISBN) Shahriari, H. R ; Sadoddin, R ; Jalili, R ; Zakeri, R ; Omidian, A. R ; Sharif University of Technology

2005

Abstract

Modeling and analysis of information system vulnerabilities helps us to predict possible attacks to networks using the network configuration and vulnerabilities information. As a fact, exploiting most of vulnerabilities result in access rights alteration. In this paper, we propose a new vulnerability analysis method based on the Take-Grant protection model. We extend the initial Take-Grant model to address the notion of vulnerabilities and introduce the vulnerabilities rewriting rules to specify how the protection state of the system can be changed by exploiting vulnerabilities. Our analysis is based on a bounded polynomial algorithm, which generates the closure of the Take-Grant graph...