Sharif Digital Repository

In this paper we claim that local optimization can produce proper start point for genetic search. We completely test this claim on partitioning problem and on the performance of genetic search in a real problem that is finding aggregation tree in the sensor networks. The presented method (named Tendency algorithm) increases the performance of heuristic searches, and can be used in parallel with other tuning methods. The paper justifies the logic behind tendency algorithm by measuring the "entropy" of solution (in regard to optimal solution), and by numerous empirical tests. © 2008 IEEE  

The critical issue in designing correlated data networks like Wireless Sensor Networks is to minimize the total cost of data transmission in the network, and decrease the amount of data flow. The problem of finding optimal aggregation tree for correlated data gathering in single sink network is considered as an NP-Complete problem and hence heuristic methods are usually applied to solve it[1]. In this paper, we apply genetic algorithm (GA) to solve the problem. In our method, we improve the performance of genetic search by selecting proper initial population. This initial population is determined in two ways, by using Prime's algorithm, and shortest path tree. The main issue is to regard... 

Route choice modeling is one of the most important parts of traffic assignment problem. Recently, this model is used to describe the reactions of drivers to Traveler Information Systems in order to develop accurate Advanced Traffic Management and Information System (ATMIS). Therefore accurate model is necessary. In this paper we proposed a new model based on Type-II fuzzy logic to model route choice problem. This model can take account of the imprecision, uncertainties and vagueness lying in the dynamic choice process and makes more accurate modeling of drivers' behavior than deterministic, stochastic and Type-I fuzzy models. In our proposed model we consider average speed and cost... 

This paper initially deals with the design of a new customized reconfigurable mobile parallel mechanism. This mechanism is called the 'Taar Reconfigurable ParaMobile' (TRPM), consisting of three mobile robots as the main actuators. Then, the kinematics and path planning for this mechanism are presented. The newly proposed mechanism is expected to circumvent some shortcomings of inspection operation in unknown environments with unexpected changes in their workspace, for example, in a water pipe with a non-uniform cross-sectional area. In this paper, 'Artificial Potential Field' (APF) has been assumed to be the path planning algorithm and its resulting attractive and repulsive forces are only... 

The first spoken dialogue system is developed for the Persian language is introduced. This is a ticket reservation system with Persian ASR and NLU modules. The focus of the paper is on learning the dialogue management module. In this work, real on-line training data are used during the learning process. For on-line learning, the effect of the variations of discount factor (γ) on the learning speed is investigated as the second contribution of the research. The optimal values for γ were found and the variation pattern of the action-value function (Q) in the learning process was obtained. A probabilistic policy for selecting actions is used in this work for the first time instead of greedy... 

This paper initially deals with the design of a new customized reconfigurable mobile parallel mechanism. This mechanism is called "Taar Reconfigurable ParaMobile (TRPM)", consisting of three mobile robots as the main actuators. Then, the kinematics and path planning for this mechanism are represented. The newly proposed mechanism is expected to circumvent some shortcomings of inspection operation in unknown environments with unexpected changes in their workspace, e.g., in a water pipe with non-uniform section area. In this paper, "Artificial Potential Field (APF)" has been assumed to be the path planning algorithm and its resulting attractive and repulsive forces are only applied to the... 

Single-task learning in artificial neural networks will be able to learn the model very well, and the benefits brought by transferring knowledge thus become limited. In this regard, when the number of tasks increases (e.g., semantic segmentation, panoptic segmentation, monocular depth estimation, and 3D point cloud), duplicate information may exist across tasks, and the improvement becomes less significant. Multi-task learning has emerged as a solution to knowledge-transfer issues and is an approach to scene understanding which involves multiple related tasks each with potentially limited training data. Multi-task learning improves generalization by leveraging the domain-specific information... 

Context Event-Driven Software (EDS) is a class of software whose behavior is driven by incoming events. Web and desktop applications that respond to user-initiated events on their Graphical User Interface (GUI), or embedded software responding to events and signals received from the equipment in its operating environment are examples of EDS. Testing EDS poses great challenges to software testers. One of these challenges is the need to generate a huge number of possible event sequences that could sufficiently cover the EDS's state space. Objective In this paper, we introduce a new six-stage testing procedure for event-driven web applications to overcome EDS testing challenges. Method The... 

Due to a rapid development of process manufacturing, composite materials with graphene-reinforcement have obtained so much commercially notices in the promoted engineering applications. With this regard, the critical voltage and frequency characteristics of a graphene nanoplatelets (GNP) composite cylindrical nanoshell coupled with the piezoelectric actuator (PIAC) are investigated. The material properties of piece-wise graphene-reinforced composites (GNPRCs) are assumed to be graded through the thickness direction of a cylindrical nanoshell and are estimated based on a nanomechanical model. For the first time, the current study is considering the effects of the piezoelectric layer, GNPRC... 

In this article, the vibration characteristics of high-speed rotating graphene-nanoplatelets (GNP)-reinforced composite cylindrical nanoshell coupled with a piezoelectric actuator (PIAC) are investigated. This composite nanostructure rotates around the axial direction, and the Coriolis and centrifugal effects are considered in the formulation. The material properties of piecewise graphene-reinforced composites (GNPRCs) are assumed to be graded in the thickness direction of the cylindrical nanoshell and estimated through a nanomechanical model. In the current study, the effects of angular velocity, piezoelectric layer, GNPRC and size-effects on the frequency of the spinning GNPRC cylindrical... 

The article Wave propagation characteristics of the electrically GNP reinforced nanocomposite cylindrical shell, written by Hamed Safarpour, was originally published electronically on the publisher’s internet portal (currently SpringerLink) on 12/04/2019 with open access. With the author(s)’ decision to step back from Open Choice, the copyright of the article changed on [07/05/2019] to © The Brazilian Society of Mechanical Sciences and Engineering 2019 and the article is forthwith distributed under the terms of copyright  

In this article, wave propagation characteristics of a size-dependent graphene nanoplatelet (GNP) reinforced composite cylindrical nanoshell coupled with piezoelectric actuator (PIAC) and surrounded with viscoelastic foundation is presented. The effects of small scale are analyzed based on nonlocal strain gradient theory (NSGT) which is an accurate theory employing exact length scale parameter and nonlocal constant. The governing equations of the GNP composite cylindrical nanoshell coupled with PIAC have been evolved using Hamilton’s principle and solved with assistance of the analytical method. For the first time in the current study, wave propagation electrical behavior of a GNP composite... 

In this research, buckling and vibrational characteristics of a spinning cylindrical moderately thick shell covered with piezoelectric actuator carrying spring-mass systems are performed. This structure rotates about axial direction and the formulations include the Coriolis and centrifugal effects. In addition, various cases of thermal (uniform, linear, and nonlinear) distributions are studied. The modeled cylindrical moderately thick shell covered with piezoelectric actuator, its equations of motion, and boundary conditions are derived by the Hamilton's principle and based on a moderately cylindrical thick shell theory. For the first time in the present study, attached mass-spring systems... 

In this research, electrically performance, vibration/resonance characteristics, low-velocity impact, and absorbed energy of the piezoelectric doubly curved panel on the viscoelastic substrate is carried out. For modeling the contact force between the structure and impactor, Hertz contact theory is presented. Hamilton's principle and first-order shear deformation theory (FSDT) are presented for obtaining the governing and boundary condition equations of the structure under the low-velocity impact. Galerkin and Newmark solution procedures are presented for solving the governing equation in displacement, and time domains, respectively. This study's novelty is considering the effect of... 

Service-Oriented Architecture (SOA) is a software design framework where distributed services are provided and used by applications over a network. By using this architecture new challenges appeared for software testing. Lack of access to the source code and runtime binding are examples of these challenges. Functional testing of services assures the quality of service-oriented applications. In this paper, we introduce a new 3-phase consumer and provider contract-based process for web service testing to overcome SOA testing challenges. Our proposed process, namely OTaaWS, consists of Test Automation, Test Execution and Test Management steps on the provider's side, which can be done on-demand.... 

This paper aims at investigating the seismic behavior of strengthened reinforced concrete (RC) shear walls using a 3D finite element analysis. A series of four different configurations of carbon fiber reinforced polymer (CFRP) composites and four different schemes of steel elements are utilized to compare the two methods of retrofitting RC shear walls with similar dimensions and reinforcement ratios. Nonlinear simulations of the RC shear walls are conducted under the action of lateral cyclic loading in ABAQUS Explicit software. In addition, the numerical modeling for RC walls strengthened by CFRP composites as well as steel elements are validated according to the previous experimental... 

Service-Oriented Architecture (SOA) is a technology for designing software systems. By using this architecture, new challenges appeared for software testing. Functional testing of services assures the quality of service-oriented applications. Herein, we introduce a new test web service named TaaWS (Test as a Web Service), which is a combination of both online testing and testing as a service to overcome SOA testing challenges. Each web service can have its test web service. Thus, the consumer can call TaaWS to assure the accuracy of the web services used in the application. TaaWS consists of semantic and structural test cases extracted from the extended-attribute grammar of the web service... 

Service-Oriented Architecture is a technology for designing software systems. Upon using this architecture, new challenges appeared for software testing in which unit testing can be viewed as the most essential and basic testing procedure. Many industrial tools and academic studies have presented a level of automation for unit testing of web services. Herein, we introduce a new tool called Sharif-TaaWS to automate the unit testing of web services through a method-based attribute grammar (MBAG) of the source code. This tool generates a test web service named TaaWS (Test as a web service), a combination of both online testing and testing as a service. Sharif-TaaWS has three modules including... 

In this paper, dynamic modeling and dynamic sensitivity analysis of an n-revolute planar serial robot are investigated. First, a dynamic modeling algorithm is proposed which is based on the concept of the so-called Natural Orthogonal Complement. The main goal of this algorithm consists in deriving the corresponding dynamic equations of a planar serial manipulator systematically. As a comparison study, 3-DOF a planar serial manipulator is modeled and the results of the proposed algorithm is compared with other methods, i.e., Newton-Euler, Lagrange-Euler, Adams software and an Open Dynamics Engine, the so-called MatODE. Then, in order to develop a dynamic sensitivity analysis scheme, Sobol's...