Kucukugurlu, Busranur; Ustubioglu, Beste; Ulutas, Guzin; Herencsar, N.

Due to the advantages of convenience, and difficulty of detection, copy-move forgery is one of the most common audio forgery forms. It is significant to decide whether there is a duplicated segment in the audio. In order to detect copy-move forgery, a new method is proposed in this paper. In the proposed algorithm, first the audio is segmented into syllables using a pitch tracking method. Second, each syllable analyzed with a 1-D local binary pattern operator. This operator calculates the histogram of each syllable. Mean square error is used to compute the similarities of histograms. The syllables which have similar histograms are detected as forged audio segments. Compared to another 1-D local binary pattern method, the proposed method has better detection results for copy-move forgery. Our experiments show that the proposed algorithm is feasible and effective, and robust against many common postprocessing operations such as noise addition, filtering, and compression.

Yazgan, Ayhan; Simsek, Cemaleddin; Albayrak, Cenk; Tugcu, Emin; Turk, Kadir; Herencsar, N.

Channel measurement for visible light communication (VLC) is theoretically and experimentally performed in a real office platform. Six armatures composed of phosphor based white LED arrays are fed by designed analog LED drivers. Measurements are taken in a 6m x 7.8m office room which is formed as 10×13 matrix with 60 cm grid distance for both simulation and experiment studies. The link distance between LED arrays and optical receiver is kept minimum 2.5 meters for each measurement. Experimental results are generally in good agreement with simulation results, which are obtained using Barry's theoretical channel model.

Simsek, Cemaleddin; Tugcu, Emin; Albayrak, Cenk; Yazgan, Ayhan; Turk, Kadir; Herencsar, N.

Visible light communication (VLC) is an emerging technology to fulfill both illumination and communication purposes considered as either an alternative or a support system for some of scenarios carried by RF communication systems. Colour shift keying (CSK) is the modulation given in IEEE 802.15.7 VLC standard which proposes Reed-Solomon as error correction code. Polar code is the first theoretically proven capacity achieving error correction code with low encoding and decoding complexities. Performance of Polar code with belief propagation decoder has not been studied under VLC CSK scheme. In this study we investigate performance of Polar code with belief propagation decoder under VLC CSK scheme and compare it with performance of Reed-Solomon code. Result show that Polar code with belief propagation decoder outperforms Reed-Solomon code by at least 1.5dB.

Simsek, Cemaleddin; Turk, Kadir; Herencsar, N.

Belief propagation (BP) polar code decoder is well-studied from many aspects. This study proposes a hardware optimization to improve performance of polar BP decoder by modifying both processing element (PE) and early stopping criterion (ESC). PE is optimized by using high-speed parallel-prefix Ling adder instead of carry ripple adder and WIB ESC introduced in literature is optimized by removing unnecessary adder array. FPGA implementation is made to verify the idea behind this study. The results show that throughput of polar code belief propagation decoder can be increase significantly by using proposed approach. More accurate comparison can be made by application specific chip design with same parameters. This part of the study will be held in future.