@article{ author = {Keshavarzi, Mohammadreza and Mohammadi, Abbas and Abdipour, Abdolali}, title = {The Impact of IQ Imbalance on the BER of Adaptive Modulation in the MIMO System}, abstract ={Abstract The effect of IQ imbalance on adaptive MQAM modulation in MIMO systems with direct conversion receivers is investigated in this paper. A continues power, discrete rate adaptive modulation scheme in using MIMO system with perfect channel information in both transmitter and receiver is considered. The selected adaptation mechanism changes the transmit power and transmit constellation size under an average transmit power and instantaneous bit error rate (BER) constraints to obtain the maximum average spectral efficiency. First, a closed from expression for the BER of MQAM modulation under the effect of IQ imbalance is introduce. Then, the impact of IQ imbalance on the BER of adaptive modulation in MIMO system is studied. This effect is also investigated for the different configuration of trancmit-recive antenna. The analytic results are compared with the Mont Carlo simulation results to verify the analytic expression.}, Keywords = {adaptive modulation, bit error rate, IQ imbalance, MIMO}, volume = {1}, Number = {1}, pages = {1-8}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-227-en.html}, eprint = {http://jor.iranaict.ir/article-1-227-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} } @article{ author = {Montazer, Gholamali and Saroukhani, Leil}, title = {Design and implementation of a fuzzy expert system for suspicious behavior detection in e-banking system}, abstract ={Abstract One of the most important obstacles to use Internet Banking is lack of security and some abuses in such systems. Therefore, fraud and suspicious behavior detection, to prevent unauthorized accesses, are of great importance in financial organizations and banks. In this paper, an expert system is designed to detect users’ unusual or suspicious behaviors in the internet banking system. As different users’ behaviors may be ambiguous and uncertain the system has been designed based on fuzzy notions in such a way that it can recognize the users’ behaviors and classify the suspicious ones according to their intensity. The proposed system has been implemented and tested on the Internet-Banking system for Bank Mellat, which has the largest on-line banking services in Iran and the results showed that the system detects successfully the unusual behavior.}, Keywords = {Internet banking, suspicious behavior, Expert system, Fuzzy theory}, volume = {1}, Number = {1}, pages = {9-18}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-228-en.html}, eprint = {http://jor.iranaict.ir/article-1-228-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} } @article{ author = {safavi, Aliakbar and Taheritehrani, mohammad and Kharazmi, Mohammad Rafiee}, title = {A new reinforcement learning based multi-agent method for traffic shaping and buffer allocation in routers}, abstract ={Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal" mso-tstyle-rowband-size:0 mso-tstyle-colband-size:0 mso-style-noshow:yes mso-style-priority:99 mso-style-qformat:yes mso-style-parent:"" mso-padding-alt:0cm 5.4pt 0cm 5.4pt mso-para-margin:0cm mso-para-margin-bottom:.0001pt mso-pagination:widow-orphan font-size:11.0pt font-family:"Calibri","sans-serif" mso-ascii-font-family:Calibri mso-ascii-theme-font:minor-latin mso-fareast-font-family:"Times New Roman" mso-fareast-theme-font:minor-fareast mso-hansi-font-family:Calibri mso-hansi-theme-font:minor-latin mso-bidi-font-family:Arial mso-bidi-theme-font:minor-bidi} Abstract In this paper, realizing the distributed structure of computer networks, the random behaviors in such networks, and the time limitations for control algorithms, the concepts of reinforcement learning and multi-agent systems are invoked for traffic shaping and buffer allocation between various ports of a router. In fact, a new traffic shaper based on token bucket has been developed. In this traffic shaper, instead of a static token production rate, a dynamic and intelligent rate based on the network condition is specified. This results in a reasonable utilization of bandwidth while preventing traffic overload in other part of the network. Besides, based on the stated techniques a new method for dynamic buffer allocation in the ports of a router is developed. This leads to a reduction in the total number of packet dropping in the whole network. Simulation results show the effectiveness of the proposed techniques.}, Keywords = {SIP, Performance Evaluation, configuration, mobility management. }, volume = {1}, Number = {1}, pages = {19-30}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-229-en.html}, eprint = {http://jor.iranaict.ir/article-1-229-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} } @article{ author = {Firouzeh, zakerHosein and Zeidaabadi-ezhad, abolghasem and Mirmohammad-Sadeghi, Hami}, title = {A Fast Method to Compute Radiation Fields of Shaped Reflector Antennas by FFT}, abstract ={Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal" mso-tstyle-rowband-size:0 mso-tstyle-colband-size:0 mso-style-noshow:yes mso-style-priority:99 mso-style-qformat:yes mso-style-parent:"" mso-padding-alt:0cm 5.4pt 0cm 5.4pt mso-para-margin:0cm mso-para-margin-bottom:.0001pt mso-pagination:widow-orphan font-size:11.0pt font-family:"Calibri","sans-serif" mso-ascii-font-family:Calibri mso-ascii-theme-font:minor-latin mso-fareast-font-family:"Times New Roman" mso-fareast-theme-font:minor-fareast mso-hansi-font-family:Calibri mso-hansi-theme-font:minor-latin mso-bidi-font-family:Arial mso-bidi-theme-font:minor-bidi} Abstract A rapid calculation method of the far-field radiation patterns of a shaped reflector antenna illuminated by a feed in an arbitrary location is reported. In this method, the equations of geometrical optics (GO) are used to calculate the reflected electric field using the radiation patterns of the feed and the parameters defining the reflector surface. These fields comprise the aperture field distribution which is integrated over the aperture plane by Fast Fourier Transform (FFT) algorithm based on low-size meshing of the aperture to yield the far-field radiation patterns and to calculate other antenna parameters. Shaped Reflector Antenna Design and Analysis Software (SRADAS) based on this numerical method can analyze and simulate all shaped reflector antennas with large dimensions in regard to the wavelength. SRADAS has been implemented and used in Information and Communication Technology Institute (ICTI) to analyze and simulate different practical parabolic and shaped reflector antennas. In order to confirm the integrity of the proposed calculation method, two practical antennas are analyzed using this software. The results are in good agreement with the results obtained by commercial software (Method of Moment) and measurement. Large shaped reflector antennas can be simulated by SRADAS fast and accurately.}, Keywords = {Reflector antenna, Radiation integrals, Two-dimensional Fast Fourier Transform (FFT), Optimum meshing size}, volume = {1}, Number = {1}, pages = {31-39}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-230-en.html}, eprint = {http://jor.iranaict.ir/article-1-230-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} } @article{ author = {Jahanbakhsh, M. and Azhari, V. and Homayoun, M. and Akbari, A.}, title = {Evaluation of SIP signaling implementation using QoS parameters}, abstract ={Normal 0 false false false EN-US X-NONE AR-SA MicrosoftInternetExplorer4 !mso]><object classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui> st1:*{behavior:url(#ieooui) } /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal" mso-tstyle-rowband-size:0 mso-tstyle-colband-size:0 mso-style-noshow:yes mso-style-priority:99 mso-style-qformat:yes mso-style-parent:"" mso-padding-alt:0cm 5.4pt 0cm 5.4pt mso-para-margin:0cm mso-para-margin-bottom:.0001pt mso-pagination:widow-orphan font-size:11.0pt font-family:"Calibri","sans-serif" mso-ascii-font-family:Calibri mso-ascii-theme-font:minor-latin mso-fareast-font-family:"Times New Roman" mso-fareast-theme-font:minor-fareast mso-hansi-font-family:Calibri mso-hansi-theme-font:minor-latin mso-bidi-font-family:Arial mso-bidi-theme-font:minor-bidi} Abstract The variety of services on IP networks and the need for network technology convergence have resulted in many access networks to adopt the IP technology. The Session Initiation Protocol (SIP) is an end to end application level protocol for establishing, terminating and modifying sessions and has experienced widespread use in IP networks due to its distinguished features such as being text based, independence from the underlying network, and more importantly supporting various types of mobility. In fact these features have lead SIP to be used as the core signaling protocol in the IP Multimedia Subsystem, which is the control plane proposed for next generation networks by the 3GPP community. Nevertheless, the performance of SIP servers when used by the millions of users of the next generation networks is not well established. In this paper we evaluate the performance of SIP servers using a test bed developed at the Iran University of Science & Technology. We consider eight different configurations for SIP server and also study the effect of using TCP and UDP as the transport protocol for SIP packets. We measure several parameters including call setup delay, call failure rate and SIP server throughput. Our results suggest that using SIP in large networks require using special techniques for balancing the load of SIP servers as well as mitigating temporary overloads. }, Keywords = {computer network, multi- agent system, buffer, router, traffic shaping. }, volume = {1}, Number = {1}, pages = {41-54}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-231-en.html}, eprint = {http://jor.iranaict.ir/article-1-231-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} } @article{ author = {RaeisSafari, M. and Ghazanfari, M. and Fathiyan, M.}, title = {COBIT A Suitable Framework for Measuring IT Governance in Organizations}, abstract ={Abstract Nowadays IT is regarded as one of the most important and strategic section in development of business that has important role in increasing competition power of banks, on the other hand IT governance is an important section in governance of banks. Key role of IT in growth and development of banks is very clear for senior managers and the important point is strategic integrity of IT and business in banks that is first goal of IT Governance. Results of researches show that average maturity of IT Governance in governmental banks is (1, 60). Level of maturity in effective usage of IT and adaptation of strategies of business with strategies of IT in governmental banks does not have good conditions. Kind of governance in governmental banks because bank industry is not competitive issue in Iran and applying mandatory rules and regulations on bank system of Iran has caused that governmental banks will not care to using electronic commerce in their business as an strategic tool.}, Keywords = { IT Governance, COBIT Framework, Governmental Banks}, volume = {1}, Number = {1}, pages = {55-65}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-232-en.html}, eprint = {http://jor.iranaict.ir/article-1-232-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} } @article{ author = {Shafieirad, M. and Shafiee, M.}, title = {Cross-layer Design for Congestion Control, Routing and Scheduling in Ad-hoc Wireless Networks with considering the Electrical Power of nodes}, abstract ={Abstract Ad hoc Wireless Networks, are networks formed by a collection of nodes through radio. In wireless networking environment, formidable challenges are presented. One important challenge is connection maintenance mechanism for power consumption. In this paper, a multi-objective optimal design is considered for ad-hoc networks which address the electrical power of nodes effects on cross-layer congestion control, routing and scheduling. We first formulate the rate and scheduling constraints. In this way, the multi-commodity flow variables are used. Then, resource allocation in networks with fixed wireless channel and single-rate devices is formulated. Since the electrical power of nodes effects are included in the design problem, we formulate resource allocation as utility and cost function, together in a maximization problem with those constraints. By dual decomposition, the resource allocation problem vertically decomposes into three sub-problems: congestion control, routing and scheduling. These three sub-problems interact through congestion and link price. Simulation results are included to verify the effectiveness of the proposed approach.}, Keywords = {ad-hoc wireless networks, congestion control, distributed algorithm, power control, cross layer design.}, volume = {1}, Number = {1}, pages = {67-79}, publisher = {): Association of Information & Communication Technology of Iran}, url = {http://jor.iranaict.ir/article-1-233-en.html}, eprint = {http://jor.iranaict.ir/article-1-233-en.pdf}, journal = {}, issn = {}, eissn = {}, year = {2009} }