Bilgisayar Mühendisliği Bölümü Koleksiyonu

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

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Browsing Bilgisayar Mühendisliği Bölümü Koleksiyonu by Publication Category "Kitap Bölümü - Uluslararası"

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    Book Part
    Effect of Inter-Block Region on Compressed Sensing Based Channel Estimation in Tds-Ofdm Systems
    (Institute of Electrical and Electronics Engineers Inc., 2016) Başaran, Mehmet; Erküçük, Serhat; Erküçük, Serhat; Şenol, Habib; Şenol, Habib; Çırpan, Hakan Ali
    Time domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) is the basis technology for digital television standard (DTV) employed in some countries thanks to its high spectral efficiency when compared to traditional cyclic prefix OFDM. Moreover, it does not require pilot usage in frequency domain channel estimation. Instead of data usage as cyclic prefix, pseudo-noise (PN) sequences are transmitted in guard intervals. Due to interference from the previous OFDM data symbol, the received signal in guard interval can be decomposed into a small-sized signal that contains only PN sequences utilizing the inter-block-interference (IBI)-free region in the convolution matrix. Due to sparsity, multipath fading channel can be obtained by the application of compressed sensing (CS) technique to reconstruct the high-dimensional sparse channel from the decreased-size of received signal through the known PN sequence matrix. In this study, the effect of the size of IBI-free region on CS and Bayesian CS (BCS) based channel estimation is investigated. Accordingly, reconstruction error performances of basis pursuit (BP) and BCS are compared. Simulation results show that the channel estimation can be improved by trading-off the length of the IBI-free region. However, an increase in IBI-free region leads to decreased energy efficiency at both the transmitter and receiver side.
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    Book Part
    First Impressions on Social Network Sites: Impact of Self-Disclosure Breadth on Attraction
    (Academic Conferences and Publishing International Limited, 2017) Baruh, Lemi; A. Bısson, Chrıstophe Louıs; Cemacılar, Zeynep; Bisson, Christophe; Chisik, Yoram I.
    This paper reports the results of two experiments that investigate the relationship between the quantity of information disclosed on an SNS profile and profile viewers' first impressions of the profile owner. Both experiments utilized a 2 (low quantity of information vs. high quantity of information) by 2 (male vs. female profile) design. In the first experiment (n = 1059), the respondents were randomly assigned to the experimental conditions. The results showed that profile viewers were more favorable to profiles of women. Also, both for female and male SNS profiles, higher quantity of information led to more positive ratings of the profile owner. The second experiment expanded the findings from the first experiment in two ways. First, in the second experiment (n = 320), rather than being randomly assigned to the profile gender condition, the respondents could pick the gender of the profile they would review. Second, informed by previous research on face to face interactions which indicate that quantity of self-disclosure can increase interpersonal attraction by reducing the level of uncertainty about relational outcomes, we tested whether uncertainty reduction mediated the relationship between quantity of information presented in an SNS profile and interpersonal attraction. Female profiles were selected more often than male profiles by both female and male respondents; however, there was no difference in interpersonal attraction ratings that male and female profiles received. Higher quantity of information presented in an SNS profile had a significant impact on interpersonal attraction. The results from the second experiment also indicated that while quantity of information positively influenced profile viewers' perceptions regarding the agreeableness of the profile owner, it did not have an impact on viewers' perceptions regarding the dependability of the profile owner. As predicted, the impact of quantity of information on interpersonal attraction was mediated by a reduction in uncertainty levels.