Browsing Elektrik-Elektronik Mühendisliği / Electrical - Electronics Engineering by Language "Turkish"
Now showing items 1-20 of 47
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A new approach for coexistence of IEEE 802.11af and IEEE 802.22 systems
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Publisher and Date:(Institute of Electrical and Electronics Engineers Inc., 2018)In this paper various algorithms are proposed to help IEEE 802.11af and IEEE 802.22 wireless systems to coexist in TV white space by considering multiple techniques. By using busy tone power control and multihop communication techniques improvements have been made compared to prior approaches. With this approach while IEEE 802.22 systems are protected from intra-network interference IEEE 802.11af systems are still able to continue transmitting packets. Considering the communication parameters and ...
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A New Technique for OFDM: OFDM-Index Modulation
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Publisher and Date:(IEEE, 2013)In this study a novel scheme called orthogonal frequency division multiplexing with index modulation (OFDMIM) is proposed for frequency selective channels. In this scheme the information is conveyed not only by only M -ary signal constellations as in classical OFDM but also by the indices of the active subcarriers which are determined according to the information bits. Different transceiver structures have been investigated for the proposed scheme and it has been shown via computer simulations ...
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A numerical method for frequency determination in the astable cellular neural networks with opposite-sign templates
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Publisher and Date:(IEEE, 2006)In this study a numerical method is proposed to determine the oscillation frequencies in the astable cellular neural networks with opposite-sign templates [1]. This method depends on the training of a multilayer perceptron that uses various template coefficients and the correspondant frequency values as inputs and outputs. First of all a frequency surface is obtained from templates and then training samples are picked from this surface in order to apply to multilayer perceptron. The effects of the ...
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A Simple Iterative Equalizer for Space Time Coded Multiple Antenna Systems
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Publisher and Date:(IEEE, 2009)In this paperg a simple low complexity iterative receiver for spacetime coded zSTCg transmission is proposed and the pen formance over frequencyyselective fast and quasistatic fading channels is investigatedF Simulation results show that the pery formance of the proposed structure improves with each iteraytionF Considering the practically prohibitive complexity of opytimal equalizersg the proposed iterative receiver can be more desirable in wireless systems with large number of antennasg big ...
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Alternative Transducer Power Gain Expression in Broadband Matching Network Designs
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Publisher and Date:(IEEE, 2016)In this paper a reflection coefficient based transducer power gain expression has been derived which is an alternative to the impedance based expression exists in the literature. A broadband double matching problem is solved by using the derived gain expression and the obtained performance has been compared with the performance obtained via the existing expression.
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Anomaly detection in walking trajectory [Yürüyüş yörüngesinde anormallik algılama]
Authors:
Publisher and Date:(Institute of Electrical and Electronics Engineers Inc., 2018)Analysis of the walking trajectory and the detection of anomalies in this trajectory provide important benefits in the fields of health and security. In this work two methods to detect anomalies in trajectories are compared. Firstly an unsupervised method is used where the conformance among trajectories are taken into consideration. Trajectories that deviate from others are qualified as anomalies. Secondly the points in the trajectories are considered as a time series. Artifical neural networks ...
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Busy tone based power control for coordination of IEEE 802.11af and 802.22 system [IEEE 802.11af ve 802.22 Sistemlerinin Uyumlu Çalışmaları için Meşgul Ton Tabanlı Güç Kontrolü]
Authors:
Publisher and Date:(Institute of Electrical and Electronics Engineers Inc., 2017)In this paper a new power control algorithm based on busy tone approach has been proposed for the coordination of IEEE 802.22 and IEEE 802.11af systems in TV white space. Different from the earlier studies in addition to both 802.11af access point and clients listening to the busy tone they also adjust their communication power according to the location information and use hopping for communication if needed. Acccordingly interference caused to 802.22 systems has been reduced while the 802.11af ...
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Busy Tone Implementation for Coexistence of IEEE 802.22 and 802.11 af Systems
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Publisher and Date:(IEEE, 2015)In this paper a new algorithm based on busy tone approach has been proposed for the coexistence of IEEE 802.22 and IEEE 802.11af systems in TV white space. Different from the earlier study in addition to 802.11af access points listening to the busy tone signal their clients also listen to the busy tone and let the access points know once they hear it. Accordingly interference caused to 802.22 systems has been reduced. This study quantifies the improved system performance in terms of interfering ...
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Comparison of Compressed Sensing Based Algorithms for Sparse Signal Reconstruction
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Publisher and Date:(IEEE, 2016)Compressed sensing theory shows that any signal which is defined as sparse in a given domain can be reconstructed using fewer linear projections instead of using all Nyquist-rate samples. In this paper we investigate basis pursuit matching pursuit orthogonal matching pursuit and compressive sampling matching pursuit algorithms which are basic compressed sensing based algorithms and present performance curves in terms of mean squared error for various parameters including signal-tonoise ratio ...
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Effect of channel estimation errors on the performance of space time coded systems with antenna selection
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Publisher and Date:(IEEE, 2007)This paper presents the effects of channel estimation errors on the performance especially diversity gain of space-time coded systems with antenna selection. We consider maximum signal to noise ratio as the antenna selection criteria. Specifically we first present the effect on the upper bound for pairwise error probability of space-time coded systems with antenna selection over flat fading channels. Moreover we provide simulation results for the antenna selection at the receiver and/or transmitter ...
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Effects of channel models and optional data rates on the IEEE 802.15.4a system performance [Kanal modellerinin ve seçime bağli veri hızlarının IEEE 802.15.4a sistem başarımına etkileri]
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Publisher and Date:(2010)The wireless personal area network standard IEEE 802.15.4a uses ultra wideband impulse radios (UWB-IRs) for precise ranging and location and as well as for communications at low data rates (about 1 Mb/s). In addition to low data rates there are optional data rates defined in the standard that can support up to 27 Mb/s. In this paper the IEEE 802.15.4a system performance is studied for optional data rates in addition to considering the effect of channel models at the mandatory data rate. For the ...
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EM-based joint data detection and channel estimation for uplink MC-CDMA systems over frequency selective channels
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Publisher and Date:(IEEE, 2007)This paper is concerned with joint channel estimation and data detection for uplink multicarrier code-division multiple-access (MC-CDMA) systems in the presence of frequency fading channel. The detection and estimation algorithm implemented at the receiver is based on a version of the expectation maximization (EM) technique which is very suitable for the multicarrier signal formats. Application of the EM-based algorithm to the problem of iterative data detection and channel estimation leads to a ...
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Fault estimation of Trakya and Marmara Sea regions using 2D Gabor filtering [2 boyutlu gabor filtre yöntemi uygulayarak Trakya ve Marmara denizindeki fay hatlarının saptanması]
Authors:
Publisher and Date:(2005)In this paper we have applied 2D Gabor filtering to gravity and magnetic anomalies in estimation of discontinuities. Gabor filtering is an effective separation method compared to others having steerable and frequency parameter properties. We have found new faults using Gabor filtering for gravity and magnetic anomalies of Marmara Sea. © 2005 IEEE.
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Iterative channel estimation for spatial modulation systems over fast fading channels
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Publisher and Date:(IEEE, 2014)Spatial Modulation (SM) based on the use of antenna indices to transmit information in addition to the conventional signal constellations has been recently proposed to solve practical problems encountered in MIMO systems. In the literature estimation of CSI for SM systems is simply investigated by RLS for slow fading channels. However iterative receivers that offer significant performance gains over a non- iterative when the total number of pilot is not sufficient and the channel is fast fading ...
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Iterative channel estimation for spatial modulation systems over fast fading channels [Hızlı sönümlemeli kanallarda uzaysal modülasyon sistemleri için iteratif kanal kestirimi]
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Publisher and Date:(IEEE Computer Society, 2014)Spatial Modulation (SM) based on the use of antenna indices to transmit information in addition to the conventional signal constellations has been recently proposed to solve practical problems encountered in MIMO systems. In the literature estimation of CSI for SM systems is simply investigated by RLS for slow fading channels. However iterative receivers that offer significant performance gains over a non-iterative when the total number of pilot is not sufficient and the channel is fast fading ...
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Iterative Receiver for DS-CDMA Systems in the Presence of Time-Varying Channels
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Publisher and Date:(IEEE, 2008)In this paper we present an efficient iterative receiver structure of tractable complexity for joint multiuser detection and multichannel estimation (JDE) of direct-sequence code-division multiple-access systems operating in the presence of time-varying flat fading channel. The time-varying channel is assumed to be modeled according to a piece-wise constant channel. An optimality criterion is defined and analytical expressions for the corresponding optimized weight coefficients are given. Monte-Carlo ...
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Iterative receiver for DS-CDMA systems in the presence of time-varying channels
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Publisher and Date:(2008)In this paper we present an efficient iterative receiver structure of tractable complexity for joint multiuser detection and multichannel estimation (JDE) ofdirect-sequence code-division multiple-access systems operating in the presence of timevarying flat fading channel. The tilne-varying channel is assumed to be modeled according to a piece-wise constant channel. An optimality criterion is defined and analytical expressions for the corresponding optimized weight coefficients are given. Monte-Carlo ...
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Joint phase noise estimation and source detection [Ortak faz gürültüsü kestirimi ve kaynak sezimlemesi]
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Publisher and Date:(2010)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 ...
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Linear Combination of Pulses for Coexistence in the IEEE 802.15.4a Standard
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Publisher and Date:(IEEE, 2009)The low data rate accurate location ranging Wireless Personal Area Network zWPAN standard IEEE which is based on ultra wideband zUWBg impulse radios suggests using linear combination of pulses to reduce interference to coexisting primary systems. In this paper we consider possible implementations of linear combination of pulses as suggested in the standard and study the generated notches in the resulting code spectrum. Using the zy transform approach we show that the number of these notches is ...
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Mobile Application Development for the Estimation of Recurrence in Post-Operative Kidney Cancer Cases
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Publisher and Date:(IEEE, 2018)In this paper a post-operative recurrence estimation tool called Sorbellini's nomogram for the kidney cancer patients showing no metastates is introduced and a novel application for mobile devices based on this model is developed for the physician's follow up procedures. The TNM stage tumor size nuclear (Fuhrman) grade the existance of necrosis and vascular invasion are employed as the input parameters for this software to predict the recurrence probability in mentioned patients. Finaly the ...
