776 research outputs found

    New Full-Diversity Space-Time-Frequency Block Codes with Simplified Decoders for MIMO-OFDM Systems

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    Multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) is known as a promising solution for wideband wireless communications. This is why it has been considered as a powerful candidate for IEEE 802.11n standard. Numerous space-frequency block codes (SFBCs) and space-time- frequency block codes (STFBCs) have been proposed so far for implementing MIMO-OFDM systems. In this paper, at first we propose new full-diversity STFBCs with high coding gain in time-varying channels; the construct method for this structure is using orthogonal space-time block code for any arbitrary number of transmit antenna and then we propose a decoder with linear complexity for our proposed coding scheme. Simulation results verify that the proposed STFBCs outperform other recently published STFBCs

    Numerical modeling of sedimentation in the Sefid-Rood Reservoir, Iran

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    River morphodynamics and sediment transportSedimentation in reservoir

    Epidemiological characteristics and incidence rate of brucellosis in Isfahan province, Iran, 2012

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    Background: Brucellosis is a common zoonotic disease, which spread from infected animals to humans .This study aimed to determine the epidemiological characteristics and incidence rate of brucellosis during 2012 in Isfahan province, Iran. Methods: This cross-sectional study assessed all the patients with diagnosis of brucellosis in Isfahan province during 2012. We used t and chi-square test for data analysis. The incidence rate was calculated based on per 100�000 of at-risk population. Findings: Totally, 575 patients with brucellosis were identified of which, 69.9 were men and 87.7 were from rural areas. Housewives-ranchers and children were the most and least at-risk individuals, respectively. The incidence of the disease was 11.13 per 100�000 of at-risk population in the province, 4.15 in male, 9.64 in women, 1.7 in urban areas and 12.9 per 100�000 of at-risk population ear in rural areas during 2012. In addition, there was significant association between the type of disease (new or recurrent) and county of residence and history of contact with animals (P < 0.05). Conclusion: The incidence of brucellosis in the Isfahan province was less than the national average, and this province classified to have very low incidence. In addition, there were clear differences in the geographical distribution of disease in the province. © Journal of Isfahan Medical School. All rights reserved

    Adaptive two layer fuzzy control of a mobile robot system

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    Development of a Fuzzy-based Multi-agent System for E-commerce Settings

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    AbstractIn this paper we present our experience in developing a fuzzy-logic based multi-agent e-commerce system capable of achieving a mutually beneficial deal for the seller and buyer using a negotiation process. We use fuzzy logic to assist users to express their preferences about a product in fuzzy terms such as low, medium and high. Our system evaluates offers based on a fuzzy utility function and feeds utility scores to a fuzzy inference system which then computes its next counter offer. Our paper presents issues involved in the development of a multi-agent system for e-commerce settings using the JADE platform - a modern agent development environment. In this paper our focus is on implementing agents of different types/roles engaged in activities usually encountered with buying and selling in an e-commerce environment. Our concluding remarks and future research are presented
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