• List of Articles


      • Open Access Article

        1 - Missile Autopilot Design Using Fuzzy Gain-Scheduling
        A. Akbarzadeh Kalat H. R. Momeni
        In this paper a controller using fuzzy gain-scheduling for the channels of a tactical missile is designed such that in flight trajectories, performance is achieved. In this design method, the fuzzy gain-scheduling zone centers are determined by a training algorithm acco Full Text
        In this paper a controller using fuzzy gain-scheduling for the channels of a tactical missile is designed such that in flight trajectories, performance is achieved. In this design method, the fuzzy gain-scheduling zone centers are determined by a training algorithm according to dynamic pressure, Mach number and coefficients of linear model of system in major operating points. The fuzzy system is learned using combined genetic and linear least squares algorithms. In this manner both global optimum solution and fast convergence are reachable. Moreover the membership functions in fuzzy inference system are chosen with special and suitable properties, which cause simple and effective scheduling process. Performance of this method is shown with case study simulation result. Manuscript Document
      • Open Access Article

        2 - An Agent-Based Parallel Programming for Grid Programming
        H. Deldari
        Computational grids have provided the usage of computational distributed resources for computation-intensive applications. The development of programs that use these capabilities is one of the challenging issues for grid computing. In this article, an effort has been ma Full Text
        Computational grids have provided the usage of computational distributed resources for computation-intensive applications. The development of programs that use these capabilities is one of the challenging issues for grid computing. In this article, an effort has been made in order to solve this problem by presenting mobile-agent-based parallel programming on the grid. The presentation of this model, which has been materialized by extending Alchemi™ grid infrastructure, adding agent properties and navigational commands that let the user to develop his/her program by using agents’ mobility and communication between them. In order to evaluate the system, algorithm of matrix multiplication as well as algorithm of finding the convex hull of a series of points have been implemented in the mentioned system. Manuscript Document
      • Open Access Article

        3 - Development of a Secure Web Service Using RUPSec
        S. M. Hosseininezhad G. Elahi P. Jaferian
        Security issues are considered as major hurdles in extensive utilization of web services in enterprise. There has been work on standards, protocols, and technologies to answer some of these concerns. Nevertheless, problems arise and the issues remain. One needs to reco Full Text
        Security issues are considered as major hurdles in extensive utilization of web services in enterprise. There has been work on standards, protocols, and technologies to answer some of these concerns. Nevertheless, problems arise and the issues remain. One needs to recognize security needs before he can tackle the task of selecting the right standard and mechanism to provide a secure system. In this paper, a case study is followed and thru that an approach for utilizing RUPSec for development of a secure web service is offered. The major objective has been to provide a way to discover and extract security needs of web services based on threats against them. Furthermore, RUPSec’s strength in pinpointing threats and security requirements is tested. Manuscript Document
      • Open Access Article

        4 - Determination of Control Variables in Power Systems to Maximum Load Restoration
        H. Afrakhte   A. Yazdian Varjani
        This paper presents a new method to maximize load restoration in faulted condition in power systems. Control variables which are used to restore maximum load include tap of power transformers, generation rescheduling, and load shedding in the worst case. Modeling is don Full Text
        This paper presents a new method to maximize load restoration in faulted condition in power systems. Control variables which are used to restore maximum load include tap of power transformers, generation rescheduling, and load shedding in the worst case. Modeling is done in three stages with various control variables arrangements. In the first stage of modeling, power transformer tap is used as a control variable. In the second stage, power transformers taps and generations rescheduling are considered. In the last stage, load shedding as another variable is added to decision variable spaces. Since the number of variables is high and final solution space can be nonlinear, genetic algorithm is used in the optimization process. The capabilities of the proposed method were assessed using IEEE-RTS test system with satisfactory results. Manuscript Document
      • Open Access Article

        5 - Experiments and New Mathematical Models for Prediction of Transformer Oil Characteristics under Environment Pressure Stress
        M. Mirzaie A. Gholami H. R. Tayebi
        Mineral oil in transformer is used for its insulation property and thermal transfer to external environment. Transformer oil is always under air pressure variation effects due to contact to external by silica gel chamber and the pressure which depends on the height of s Full Text
        Mineral oil in transformer is used for its insulation property and thermal transfer to external environment. Transformer oil is always under air pressure variation effects due to contact to external by silica gel chamber and the pressure which depends on the height of sea level. Therefore air pressure can affect on insulation parameters and its age. Air pressure changing can cause oil viscosity variation. In this paper, the air pressure effects on oil properties are studied by the use of tests carried out and measuring of the insulation characteristics. In a laboratory environment, air pressure was changed from 40 to 1250 mmHg using a pump. Then conductivity/leakage current and breakdown voltage are measured and analyzed. These results are used to presenting estimation models and also for suggestion of a new simple model by mathematical methods and then the models were compared to each other. Manuscript Document
      • Open Access Article

        6 - An Antenna Radiation Pattern Measurement System at Ordinary Room Using Adaptive Filter
        J. Dianat Ch. Ghobadi J. Nourinia
        In this work the inverse transfer function of the measurement room is obtained using a linear and RLS (recursive least-squares algorithm) adaptive filter. At first, an antenna with known pattern (reference antenna) is placed in the test zone to obtain the optimal tap we Full Text
        In this work the inverse transfer function of the measurement room is obtained using a linear and RLS (recursive least-squares algorithm) adaptive filter. At first, an antenna with known pattern (reference antenna) is placed in the test zone to obtain the optimal tap weights of the adaptive filter. Once the filter converges, the learning stage finishes. After that the reference antenna is replaced with the test antenna and its pattern is measured and the data of the measurement is filtered by the optimal tap weights adaptive filter. The filter cancels the stray signals (reflected and scattered signal) and produces the radiation pattern of the test antenna. This technique is superior to that of others because it has better accuracy and it is less costly. Manuscript Document
      • Open Access Article

        7 - Nastaliq CAPTCHA
        M. H. Shirali-Shahreza M. Shirali-Shahreza
        Nowadays, many daily human activities such as education, trade, talks, etc are done by using the Internet. In such things as registration on Internet web sites, hackers write programs to make automatic false registration that waste the resources of the web sites while i Full Text
        Nowadays, many daily human activities such as education, trade, talks, etc are done by using the Internet. In such things as registration on Internet web sites, hackers write programs to make automatic false registration that waste the resources of the web sites while it may also stop it from functioning. Therefore, human users should be distinguished from computer programs. To this end, this paper presents a method for distinction of Persian and Arabic-language users from computer programs based on Persian and Arabic texts using Nastaliq font. In this method, the image of a Persian or Arabic word written in Nastaliq font is chosen from a dictionary, and it is shown to the user, then he is asked to type it. Considering that the presently available Persian and Arabic OCR programs cannot identify these words, the word can be identified only by a Persian or Arabic-language user. The proposed method has been implemented by the Java language. Manuscript Document