Bilgisayar Mühendisliği Bölümü Koleksiyonu

Permanent URI for this collectionhttps://gcris.khas.edu.tr/handle/20.500.12469/45

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Citation Count: 1
An Analysis for the Use of Compressed Sensing Method in Microwave Imaging
(IEEE, 2017) Çalışkan, Cafer; Tekbaş, Mustafa; Ünal, İlhami; Erdoğan, Sercan; Çalışkan, Cafer
One of the most important problems encountered in microwave imaging methods is intensive data processing traffic that occurs when high resolution and real time tracking is desired. Radar signals can be recovered without loss of data with a randomly selected subset of the measurement data by compression sensing (CS) method which has been popular in recent years. For this reason, in this study, the use and capabilities of the CS method were investigated for tracking moving human, and the target information was correctly determined for the data obtained much below the Nyquist sampling criterion. In this study, it was revealed that the CS method can be developed for target detection and tracking
Citation Count: 1
An analysis for the use of compressed sensing method in microwave imaging [Mikrodalga Görüntülemede Sıkıştırılmış Algılama Yönteminin Kullanımına Yönelik Bir Analiz]
(Institute of Electrical and Electronics Engineers Inc., 2017) Çalışkan, Cafer; Tekbaş, Mustafa; Ünal, İlhami; Erdogan, Sercan; Çalışkan, Cafer
One of the most important problems encountered in microwave imaging methods is intensive data processing traffic that occurs when high resolution and real time tracking is desired. Radar signals can be recovered without loss of data with a randomly selected subset of the measurement data by compression sensing (CS) method which has been popular in recent years. For this reason in this study the use and capabilities of the CS method were investigated for tracking moving human and the target information was correctly determined for the data obtained much below the Nyquist sampling criterion. In this study it was revealed that the CS method can be developed for target detection and tracking. © 2017 IEEE.
Citation Count: 0
Büyük Patlama – Büyük Çöküş Optimizasyon Yöntemi Kullanılarak Bluetooth Tabanlı İç Mekan Konum Belirleme Sisteminin Doğruluğunun İyileştirilmesi
(Süleyman Demirel Üniversitesi, 2018) Arsan, Taner
Düşük enerjili Bluetooth işaretçi (Bluetooth low energy - BLE beacon) teknolojisi, iç mekan konum belirleme sistemlerinde başarılı ve düşük maliyetli çözümler sunan gelişmekte olan bir teknolojidir. Bu çalışmada, BLE işaretçileri (beacons) kullanan bir iç mekan konum belirleme sistemi geliştirilmiş, kullanılan ilave algoritmalarla standart sensörlerden elde edilen konum değerlerinin doğruluğunun artırılması amaçlanmıştır. Bunun için, deneysel iç mekan konum algılama sisteminden elde edilen konum bilgilerine Büyük Patlama – Büyük Çöküş (Big Bang – Big Crunch (BB-BC)) optimizasyon yöntemi uygulanmış ve konum doğruluğunun geliştirildiği yapılan testlerle kanıtlanmıştır. Test alanı olarak, 9,60 m × 3,90 m boyutundaki 37,44 m2'lik alan seçilmiş ve 2,40 m × 1,30 m boyutundaki oniki tane ızgara alanına ayak izi (fingerprinting) algoritması uygulanmıştır. Test alanına dört tane BLE işaretçi (beacon) yerleştirilmiş, on iki test alanından 150 saniye boyunca toplam 9.000 ölçüm yapılmıştır. Ölçüm sonuçları Büyük Patlama – Büyük Çöküş optimizasyon yöntemi ile Öklid uzaklık eşleştirme yöntemi ve Kalman Filtresi kullanılarak iyileştirilmiş, bu sayede konum doğruluğu %26,62'den %75,69'a arttırılmıştır.
Citation Count: 0
Büyük patlama büyük çöküş optimizasyon yöntemi ile ultra geniş band sensörlerinin iç mekân konum belirleme doğruluklarının iyileştirilmesi
(Pamukkale Üniversitesi, 2018) Arsan, Taner
Ultra geniş band teknolojisi, birçok iç mekân konum belirleme sisteminde başarılı çözümler sunan, diğer yöntemlere kıyasla daha iyi performans gösteren, gelişmekte olan bir teknolojidir. Bu çalışmada, ultra geniş band (Ultra Wide Band-UWB) sensörler kullanılarak bir iç mekân konum belirleme sistemi geliştirilmiş ve kullanılan ek algoritmalarla, standart donanımların sağladığı doğruluk düzeyi arttırılırken aynı zamanda ortalama hatayı azaltmak hedeflenmiştir. Bu amaçla Büyük Patlama - Büyük Çöküş (Big Bang-Big Crunch veya BB-BC) optimizasyon yöntemi deneysel iç mekân konumlandırma sistemine uygulanmış ve ölçüm doğruluğu üzerindeki olumlu etkisi yapılan testlerle kanıtlanmıştır. Test alanı olarak 7.35 m × 5.41 m boyutlarında 39.76 m2 'lik bir alan seçilmiş ve özel olarak tasarlanmış bir tavan sistemine yerden 2.85 m yüksekliğe üç farklı UWB alıcı yerleştirilmiş ve 182 adet test noktasından 60 sn.süreyle toplam 10.920 ölçüm alınmıştır. Ölçüm sonuçları Büyük Patlama - Büyük Çöküş optimizasyon algoritması ile düzeltilerek, ortalama hatası önceki 20.72 cm değerinden 15.02 cm’ye düşürülmüş, böylelikle ölçüm sonuçlarının doğruluğu arttırılmıştır.
Citation Count: 0
Effect of the Channel Estimation Error on the Performance of the Source Estimator in a Wireless Sensor Network with Orthogonal Channels
(IEEE, 2008) Şenol, Habib; Tepedelenlioğlu, Cihan
In this work effect of the channel estimation error on the MSE performance of the source estimator in a wireless sensor network with orthogonal flat fading channels is studied. A two-phase approach was employed where in the first phase the orthogonal fading channel coefficients are estimated and in the second phase channel estimates and sensor observations transmitted to fusion center are used for the source estimation. We consider a sensor network in which the channel estimates are fed-back to the sensors for optimal power allocation which leads to switch off the sensors with bad channels in the second phase. We also show that training power should be at least half of the total power. Our analytical findings are corroborated by simulation results.
Citation Count: 1
Improvement of indoor positioning accuracy of ultra-wide band sensors by using big bang-big crunch optimization method
(Pamukkale Univ, 2018) Arsan, Taner
Ultra-wide Band technology is an emerging technology that offers successful solutions in many indoor positioning systems and performs better than other methods. In this study an indoor positioning system using Ultra-wide Band (UWB) sensors was developed and it was aimed to increase the accuracy level of the standard equipment with the additional algorithms used while reducing the average error. For this purpose the Big Bang-Big Crunch (BB-BC) optimization method has been applied to the experimental indoor positioning system and the positive effect on the measurement accuracy has been proved by the tests made. An area of 39.76 m(2) was selected as a test area of 7.35 m x 5.41 m and three different Ultra-wide Band receivers were installed at a height of 2.85 m on a specially designed ceiling system and a total of 10.920 measurements were taken from 182 test points for 60 seconds. By correcting the measurement results with the Big Bang Big Crunch optimization algorithm the average error was reduced from the previous 20.72 cm to 15.02 cm thus the accuracy of the measurement results were improved.
Citation Count: 0
Joint phase noise estimation and source detection [Ortak faz gürültüsü kestirimi ve kaynak sezimlemesi]
(2010) Şenol, Habib; Şenol, Habib; Panayırcı, Erdal
Rapidly time-varying and random disturbing effects on the phase of a signal waveform are known as phase noise. In this paper we consider the problem of joint detection of continuous-valued information source output and estimation of a phase noise by using expectation maximization (EM) algorithm. In order to estimate phase noise initial phase noise values are determined by cubic interpolation that utilizes pilot symbols. Computer simulations are performed for the proposed algorithm and the average mean square error (MSE) - signal to noise ratio (SNR) performance of source detector and phase noise estimator is presented for each iteration of the algorithm. Moreover average MSE - pilot spacing performance curves of phase noise estimator are given for various SNR values. ©2010 IEEE.
Citation Count: 0
MULTI-STATE VIDEO TRANSMISSION WITH NETWORK CODING
(IEEE, 2018) Şengel, Öznur; Ekmekçi Flierl, Sıla
The goal of this work is to send video packets to all nodes in the network by enveloping Multi-State Video Coding (MSVC) at the same time network coding to maximize the throughput and video quality. This work has two main parts: 1) Multi-State Video Coding and 2) Network Coding. The main purpose of this work is to maximize not only the video quality but also the network throughput. We used Multi-State Video Coding to achieve robustness and we used network coding to increase throughput over the network. After generating the two subsequences using MSVC, we apply network coding to support transmission of packets. In this manner, we aim to increase the throughput as well as robustness and quality of the video transmission.
Citation Count: 0
Multi-state video transmission with network coding [A? kodlama ile çoklu durum video iletimi]
(Institute of Electrical and Electronics Engineers Inc., 2018) Şengel, Öznur; Ekmekçi Flierl, Sıla
The goal of this work is to send video packets to all nodes in the network by enveloping Multi-State Video Coding (MSVC) at the same time network coding to maximize the throughput and video quality. This work has two main parts: 1) Multi-State Video Coding and 2) Network Coding. The main purpose of this work is to maximize not only the video quality but also the network throughput. We used Multi-State Video Coding to achieve robustness and we used network coding to increase throughput over the network. After generating the two subsequences using MSVC we apply network coding to support transmission of packets. In this manner we aim to increase the throughput as well as robustness and quality of the video transmission. © 2018 IEEE.
Citation Count: 0
Routing performance analysis of opportunistic networks with flooding and partial flooding methods [Fırsatçı a?larda taşırma ve kısmi taşırma yöntemleriyle yönlendirme performans analizi]
(IEEE, 2012) Dağ, Tamer; Günel, Kadir; Koç, Tuğba; Sökün, Hamza Ümit; Dağ, Tamer
Opportunistic networks is one of the fast developing research areas in mobile communications. Under opportunistic networks mobile nodes try to communicate with other nodes without any prior information and knowledge about the network topology. Furthermore network topologies are dynamic and can rapidly change. In addition communication under opportunistic networks is erratic thus routes between a source node and a destination node sometimes might not exist. These issues would make classical routing approaches insufficient and unusable for opportunistic networks. In this paper two routing approaches for opportunistic networks are proposed. The first approach is flooding. Under flooding it is possible to reach a destination node with the minimum number of hops and minimum delay but with maximum network traffic. The second approach is selective flooding.The aim of selective flooding is to decrease network traffic by randomly selecting neighbor nodes and routing traffic through them. This paper explains these two approaches and compares their performance through various simulations. © 2012 IEEE.
Citation Count: 0
Sparse underwater acoustic channel estimation in colored Gaussian noise [Renkli? Gauss gürültülü seyrek sualtı akusti?k kanalların kestirimi]
(IEEE, 2012) Şenol, Habib; Şenol, Habib; Panayırcı, Erdal; Uysal, Murat
Cooperative underwater acoustic communication systems come into prominence in recent years. Since underwater channels are sparse and additive noise entering the system is colored Gaussian noise. Therefore it is very difficult to estimate the underwater channels and theoretically makes it interesting. In this study the transmission from source to the target recipient is realized by means of a relay system. Orthogonal frequency division multiplexing (OFDM)-based channel estimation problem is solved by using the matching pursuit (MP) algorithm and we obtained excellent error performance.

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