Telfor Journal Vol.6 No.2 (2014)
Content
Editorial
Editor-in-Chief:
Prof. Dr Đorđe Paunović
A Survey of Cyber Crime in Greece
A. Papanikolaou, V. Vlachos, A. Papathanasiou, K. Chaikalis, M. Dimou, and M. Karadimou
- Topic:
- Telecommunications Services
- Abstract
- During the past years, the Internet has evolved into the so-called “Web 2.0”. Nevertheless, the wide use of the offered Internet services has rendered individual users a potential target to cyber criminals. The paper presents a review and analysis of various cyber crimes, based on the cases that were reported to the Cyber Crime and Computer Crime Unit of the Greek Police Force and compares them to similar data of other EU countries.
- Keywords
- Cyber crime, Greek cyber crime, EU cyber crime.
- Full Text
- A Survey of Cyber Crime in Greece
- Page(s)
- 86-91
Performance Analysis of Dual-Hop Relay System over Ricean Fading Channels
M. Delibasic, M. Pejanovic-Djurisic, and R. Prasad
- Topic:
- Radio Communications
- Abstract
- In this paper we present an analytical model for the performance evaluation of dual-hop amplify-and-forward relay transmission over non-identical Ricean fading channels on both hops. The probability density function (PDF) and moment generating function (MGF) of total received SNR (signal-to-noise ratio) are presented as a fast converging sum. Furthermore, adequate semi-closed form expressions for average bit error rate (BER) and outage probability (OP) are derived. Numerical and simulation results confirm the validity of the proposed analytical model. Additionally, we have analyzed the impact of unbalanced SNRs of the two hops on the error performance of the considered relay system.
- Keywords
- amplify-and-forward, bit error rate, Ricean fading.
- Full Text
- Performance Analysis of Dual-Hop Relay System over Ricean Fading Channels
- Page(s)
- 92-96
Design of GNSS Performance Analysis and Simulation Tools as a Web Portal
S. Tadic, G. Moura, and T. Trichaud
- Topic:
- Radio Communications
- Abstract
- This paper considers design of a web-portal for the validation of behavior of GNSS applications in different environments. The tool provides the positioning performance analysis and a comparison to benchmark devices. Web-portal incorporates a 3D synthetic data generator to compute the propagation and the reception of radio-navigation signals in a 3D virtual environment. This radio propagation simulator uses ray-tracing to calculate interactions between the GNSS signal and the local environment. For faster execution on a GPU platform, the simulator uses BVH optimization. The work is verified in field trials and by using reference software.
- Keywords
- GNSS, EGNOS, datapool, simulation, BVH.
- Full Text
- Design of GNSS Performance Analysis and Simulation Tools as a Web Portal
- Page(s)
- 97-102
A latency analysis for M2M and OG-like traffic patterns in different HSPA core network configurations
M. V. Popović, D. D. Drajić, and S. M. Krčo
- Topic:
- Communications Systems
- Abstract
- In this paper we present an analysis intended to reveal possible impacts of core network features on latency for modelled M2M and Online Gaming traffic. Simulations were performed in a live 3G/HSPA network. Test traffic simulating multiplayer real-time games and M2M applications was generated on 10 mobile phones in parallel, sending data to a remote server. APNs with different combinations of hardware and features (proxy server, different GGSNs and firewalls, usage of Service Awareness feature) were chosen. The traffic was recorded on the Gn interface in the mobile core. The goal of experiments was to evaluate any eventually significant variation of average recorded RTTs in the core part of mobile network that would clearly indicate either the impact of used APN on delay for a specific traffic pattern, or selectivity of the APN towards different traffic patterns.
- Keywords
- Core network delay, HSPA, Latency, M2M, Online Gaming, RTT.
- Full Text
- A latency analysis for M2M and OG-like traffic patterns in different HSPA core network configurations
- Page(s)
- 103-108
Building a Speech Repository for a Serbian LVCSR System
S. Suzić, S. Ostrogonac, E. Pakoci, and M. Bojanić
- Topic:
- Signal Processing
- Abstract
- This paper describes the procedure of collecting speech and corresponding textual data and the processing needed to create a repository for training a LVCSR system for the Serbian language. The speech database for Serbian consists of speech recordings from audio books, radio programmes and talk shows, as well as read utterances from an array of male and female speakers. Currently, approximately 200 hours of speech recordings are collected, together with corresponding orthographic transcriptions which contain around 200 thousand words (over 3 million characters).Audio files are split in order for each of them to contain a single utterance. The corresponding transcriptions are used to create label files as well as for training the language model (LM) – namely, new transcriptions are added to the existing textual corpus earlier collected for the purpose of creating the LM. The software which was specially designed for building the speech repository for Serbian is also briefly described.
- Keywords
- large vocabulary continuous speech recognition, Serbian, speech database.
- Full Text
- Building a Speech Repository for a Serbian LVCSR System
- Page(s)
- 109-114
Sparse Covariance Fitting Method for Direction of Arrival Estimation of Uncorrelated Wideband Signals
S. Pejoski and V. Kafedziski
- Topic:
- Signal Processing
- Abstract
- We propose a new direction of arrival estimation method for wideband uncorrelated signals. The wideband signals are first decomposed into narrowband signals. A group sparse Lasso formulation is proposed that jointly fits the powers of the signals using overcomplete dictionaries of the directions of arrival, into the estimated covariance matrices for all narrowband signals. Then, we propose a new formulation that determines the regularization parameters and becomes the group Lasso formulation. Additionally, we propose a modified algorithm for direction of arrival estimation with lower complexity that uses conventional based methods in the preprocessing stage to reduce the number of variables in the optimization task. We compare the performance of the proposed method to the conventional methods for a circular antenna array.
- Keywords
- COMET, covariance fitting, direction of arrival estimation, group sparse Lasso, wideband signals.
- Full Text
- Sparse Covariance Fitting Method for Direction of Arrival Estimation of Uncorrelated Wideband Signals
- Page(s)
- 115-120
Inverse Multifractal Analysis of Different Frame Types of Multiview 3D Video
A. Zeković and I. Reljin
- Topic:
- Multimedia
- Abstract
- In this paper, the results of multifractal characterization of multiview 3D video are presented. Analyses are performed for different views of multiview video and for different frame types of video. Multifractal analysis is performed by the histogram method. Due to the advantages of the selected method for determining the spectrum, the inverse multifractal analysis of multiview 3D video was also possible. A discussion of the results obtained by the inverse multifractal analysis of multiview 3D video is presented, taking into account the frame type and whether the original frames belong to the left or right view of multiview 3D video. In the analysis, publicly available multiview 3D video traces were used.
- Keywords
- 3D video, frame types, inverse multifractal analysis, multiview coding.
- Full Text
- Inverse Multifractal Analysis of Different Frame Types of Multiview 3D Video
- Page(s)
- 121-125
Acoustic Vocal Tract Model of One-year-old Children
M. Vojnović, I. Bogavac, and L. Dobrijević
- Topic:
- Multimedia
- Abstract
- The physical shape of vocal tract and its formant (resonant) frequencies are directly related. The study of this functional connectivity is essential in speech therapy practice with children. Most of the perceived children’s speech anomalies can be explained on a physical level: malfunctioning movement of articulation organs. The current problem is that there is no enough data on the anatomical shape of children’s vocal tract to create its acoustic model. Classical techniques for vocal tract shape imaging (X-ray, magnetic resonance, etc.) are not appropriate for children. One possibility is to start from the shape of the adult vocal tract and correct it based on anatomical, morphological and articulatory differences between children and adults. This paper presents a method for vocal tract shape estimation of the child aged one year. The initial shapes of the vocal tract refer to the Russian vowels spoken by an adult male. All the relevant anatomical and articulation parameters, that influence the formant frequencies, are analyzed. Finally, the hypothetical configurations of the children’s vocal tract, for the five vowels, are presented.
- Keywords
- formant frequencies, larynx height index, maximal vowel spaces, speech therapist, vocal tract shape, vowel.
- Full Text
- Acoustic Vocal Tract Model of One-year-old Children
- Page(s)
- 126-130
A High-Throughput and Low-Complexity H.264/AVC Intra 16×16 Prediction Architecture for HD Video Sequences
M. Orlandić and K. Svarstad
- Topic:
- Applied Electronics
- Abstract
- H.264/AVC compression standard provides tools and solutions for an efficient coding of video sequences of various resolutions. Spatial redundancy in a video frame is removed by use of intra prediction algorithm. There are three block-wise types of intra prediction: 4×4, 8×8 and 16×16. This paper proposes an efficient, low-complexity architecture for intra 16×16 prediction that provides real-time processing of HD video sequences. All four prediction (V, H, DC, Plane) modes are supported in the implementation. The high-complexity plane mode computes a number of intermediate parameters required for creating prediction pixels. The local memory buffers are used for storing intermediate reconstructed data used as reference pixels in intra prediction process. The high throughput is achieved by 16-pixel parallelism and the proposed prediction process takes 48 cycles for processing one macroblock. The proposed architecture is synthesized and implemented on Kintex 705 -XC7K325T board and requires 94 MHz to encode a video sequence of HD 4k×2k (3840×2160) resolution at 60 fps in real time. This represents a significant improvement compared to the state of the art.
- Keywords
- H.264/AVC, encoder, intra prediction, FPGA, hardware implementation, plane mode.
- Full Text
- A High-Throughput and Low-Complexity H.264/AVC Intra 16×16 Prediction Architecture for HD Video Sequences
- Page(s)
- 131-136
Singularity Extraction for Reflected Sommerfeld Integrals over Multilayered Media
V. V. Petrovic, A. J. Krneta, and B. M. Kolundzija
- Topic:
- Applied Electromagnetics
- Abstract
- A new analytical-numerical method based on singularity extraction is presented for efficient and accurate evaluation of one of the reflected Sommerfeld integrals over multilayered media backed by a conducting (PEC) plane. Method is based on extraction of all the poles of the integrand. The method is demonstrated on one element of the tensor multilayered Green’s function, where only the singular part of the integrand, i.e. the reflection coefficient, is taken into consideration, as the cause of the largest calculation difficulties. It was also shown that the method practically eliminates all the branch cut singularities except for one.
- Keywords
- Sommerfeld integrals, singularity extraction, multilayered media
- Full Text
- Singularity Extraction for Reflected Sommerfeld Integrals over Multilayered Media
- Page(s)
- 137-141
A Comparison of Fast Marching, Fast Sweeping and Fast Iterative Methods for the Solution of the Eikonal Equation
A. Capozzoli, C. Curcio, A. Liseno, and S. Savarese
- Topic:
- Applied Electromagnetics
- Abstract
- We compare the computational performance of the Fast Marching Method, the Fast Sweeping Method and the Fast Iterative Method to determine a numerical solution to the eikonal equation. We point out how the Fast Iterative Method outperforms the other two thanks to its parallel processing capabilities.
- Keywords
- Eikonal equation, Fast Marching, Fast Sweeping, Fast Iterative, CUDA, GPUs.
- Full Text
- A Comparison of Fast Marching, Fast Sweeping and Fast Iterative Methods for the Solution of the Eikonal Equation
- Page(s)
- 142-147
Telfor Journal appreciates the support we have received from the reviewers. The following is the alphabetic list of the reviewers who have submitted one or more reviews for the current volume of Telfor Journal.
Branislav Atlagic, Aleksej Avramovic, Žarko Barbarić, Milan Bjelica, Milana Bojanić, Zoran Bojkovic, Milos Borenovic, Irina Branovic, Djuradj Budimir, Tomasz Bujlow,
Milan Cabarkapa, Jelena Ćertić, Zoran Čiča, Dejan Ćirić, Vesna Crnojevic Bengin, Vlado Delić, Bojan Dimitrijevic, Borislav Djordjevic, Radivoje Djuric, Jovan Đorđević, Dejan Drajić, Dušan Drajić, Miljko Erić, Octavian Fratu, Slavko Gajin, Ana Gavrovska, Nataša Gospić, Stevica Graovac, Tatjana Grbić, Simona Halunga, Toni Janevski,
Slobodan Jovičić, Vladimir Katic, Nenad Kojic, Aleksandar Kostić, Nenad Krajnović, Srdjan Krco, Goran Kvascev, Maja Lutovac, Miroslav Lutovac, Goran Marković,
Suzana Markovic, Miomir Mijic, Dejan Milic, Nenad Milošević, Boško Nikolić, Zorica Nikolić, Predrag Pejović, Neda Pekarić-Nađ, Lucian Perisoara, Majda Petric, Grozdan Petrović, Miodrag Popović, Mirjana Popovic, Miroslav Popovic, Milka Potrebic, Ninko Radivojević, Igor Radusinovic, Siniša Randjić, Branimir Reljin, Irini Reljin,
Natasa Reljin, Aleksandar Rodic, Andreja Samčović, Igor Simić, Mira Simic, Nikola Slavković, Vladimir Slavković, Mirjana Stojanovic, Suzana Stojkovic,
Zlatan Stojković, Aleksandar Sugaris, Dragana Šumarac Pavlović, Branislav Todorović, Mila Todorovic - Tirnanic, Dejan Tošić, Mladen Veinovic, Zoran Veljović, Milos Vujisic, Pavle Vuletic, Matej Zajc, Goran Zajić.