قلم

وبلاگ امیرحسین حاجی حسینی

قلم

وبلاگ امیرحسین حاجی حسینی

قلم

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۵ مطلب با کلمه‌ی کلیدی «Seyed Ali Ghorashi» ثبت شده است

A Fingerprint method for Indoor Localization using Autoencoder based Deep Extreme Learning Machine

Zahra Ezzati Khatab, Amirhosein Hajihoseini and Seyed Ali Ghorashi

Abstract:

By growing the demand for location based services in indoor environments in recent years, fingerprint based indoor localization has attracted many researchers' interest. The fingerprint localization method works based on received signal strength (RSS) in Wireless Sensor Networks (WSNs). This methods uses RSS measurements from available transmitter sensors, which are collected by a smart phone with internal sensors. In this paper, we propose a novel algorithm that takes the advantages of deep learning, extreme learning machine (ELM) and high level extracted features by autoencoder, to improve the localization performance in the feature extraction and the classification. Furthermore, as the fingerprint database needs to be updated (due to the dynamic nature of environment), we also increase the number of training data, in order to improve the localization performance, gradually. Simulation results indicate that the proposed method provides a significant improvement in localization performance, by using high level extracted features by autoencoder, and increasing the number of training data.
۰ نظر موافقین ۰ مخالفین ۰ ۱۷ دی ۹۶ ، ۱۰:۲۲

Distributed Spectrum Sensing for Cognitive Radio Sensor Networks using Diffusion Adaptation

Amirhosein Hajihoseini, Seyed Ali Ghorashi

Abstract:

Cognitive radio is a practical solution for spectrum scarcity. In cognitive networks, unlicensed (secondary) users should sense the spectrum before any usage, to make sure that the licensed (primary) users do not use the spectrum at that time. Due to the importance of spectrum sensing in cognitive networks, this should be fast and reliable, particularly in networks with communication link failure, which leads to network topology change. Decentralized decision making algorithms are known as a promising technique to provide reliability, scalability and adaptation, especially in sensor networks. In this paper, we propose a distributed diffusion based method in which, secondary users (sensors) cooperate to improve the performance of spectrum sensing. The proposed method provides a significant improvement in convergence rate and reliability. Simulation results indicate that the proposed algorithm shows an acceptable performance and converges twice faster than recently proposed consensus based spectrum sensing algorithms in the literature, and is almost insensitive to communication link failure.

link of paper

۰ نظر موافقین ۰ مخالفین ۰ ۱۰ مرداد ۹۶ ، ۱۰:۳۶

Decentralized Consensus Based Target Localization in Wireless Sensor Networks

Amirhosein Hajihoseini Gazestani, Reza Shahbazian, Seyed Ali Ghorashi

Abstract:

Target localization is an attractive subject for modern systems that utilize different types of distributed sensors for location based services such as navigation, public transport, retail services and so on. Target localization could be performed in both centralized and decentralized manner. Due to drawbacks of centralized systems such as security and reliability issues, decentralized systems are become more desirable. In this paper, we introduce a new decentralized and cooperative target localization algorithm for wireless sensor networks. In cooperative consensus based localization, each sensor knows its own location and estimates the targets position using the ranging techniques such as received signal strength. Then, all nodes cooperate with their neighbours and share their information to reach a consensus on targets location. In our proposed algorithm, we weight the received information of neighbour nodes according to their estimated distance toward the target node. Simulation results confirm that our proposed algorithm is faster, less sensitive to targets location and improves the localization accuracy by 85% in comparison with distributed Gauss–Newton algorithm.

link of paper

۰ نظر موافقین ۰ مخالفین ۰ ۰۹ مرداد ۹۶ ، ۱۷:۲۸

Distributed Target Localization in Wireless Sensor Networks using Diffusion Adaptation

Amirhosein Hajihoseini, Seyed Ali Ghorashi

Abstract:

Localization is an important issue for wireless sensor networks. Target localization has attracted many researchers who work on location based services such as navigation, public transportation and so on. Localization algorithms may be performed in a centralized or distributed manner. In this paper we apply diffusion strategy to the Gauss Newton method and introduce a new distributed diffusion based target localization algorithm for wireless sensor networks. In our proposed method, each node knows its own location and estimates the location of target using received signal strength. Then, all nodes cooperate with their neighbors and share their measurements to improve the accuracy of their decisions. In our proposed diffusion based algorithm, each node can localize target individually using its own and neighbor’s measurements, therefore, the power consumption decreases. Simulation results confirm that our proposed method improves the accuracy of target localization compared with alternative distributed consensus based target localization algorithms.  Our proposed algorithm is also shown that is robust against network topology and is insensitive to uncertainty of sensor nodes’ location.

Link of paper

۰ نظر موافقین ۰ مخالفین ۰ ۱۲ شهریور ۹۵ ، ۱۰:۲۵

مروری بر روش‏ های موقعیت ‏یابی در شبکه ‏های حسگر بی‏سیم با استفاده از الگوریتم ‏های شناسایی آماری الگو

امیرحسین حاجی حسینی، رضا شهبازیان، سیدعلی قرشی، داوود غرویان

چکیده:

استقرار یک سامانه ی موقعیت یابی برای گره های حسگر، یک مسئله ی اساسی برای بسیاری از کاربردها در شبکه های حسگر بی سیم است. از آنجا که ممکن است شبکه ی حسگر در منطقه ای غیرقابل دسترس مستقر شده باشد، ممکن است موقعیت حسگرها از قبل مشخص نباشد. بنابراین یک سامانه ی موقعیت یابی لازم است تا اطلاعات مکانی و موقعیت گره ها را در اختیار قرار دهد. در بسیاری از موارد قیمت و منابع محدود انرژی، اجازه‏ی تجهیز تمامی حسگر ها را به سامانه‏ی موقعیت یابی جهانی نمی دهد. لذا روش هایی لازم است تا گره ها و حسگرها بتوانند موقعیت خود را در شبکه تخمین زنند. در این مقاله سعی داریم روش های مبتنی بر الگوریتم های شناسایی آماری الگو که در زمینه ی موقعیت یابی در شبکه ی حسگر بی سیم استفاده شده اند را معرفی و عملکرد آن ها را مقایسه نماییم. با توجه به کاربردهای گسترده ای که الگوریتم های شناسایی آماری الگو دارند، این مبحث در سال های اخیر توجه زیادی را در شاخه های مختلف علوم به خود جلب کرده است و می تواند برای دسته‏بندی اطلاعات و شناسایی الگوی آن‏ها به کار رود.

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۰ نظر موافقین ۰ مخالفین ۰ ۱۲ اسفند ۹۴ ، ۱۰:۱۹