International Journal of Communications

E-ISSN: 1998-4480
Volume 10, 2016

Notice: As of 2014 and for the forthcoming years, the publication frequency/periodicity of NAUN Journals is adapted to the 'continuously updated' model. What this means is that instead of being separated into issues, new papers will be added on a continuous basis, allowing a more regular flow and shorter publication times. The papers will appear in reverse order, therefore the most recent one will be on top.

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Volume 10, 2016

Title of the Paper: High Efficient Video Coding (HEVC) Performance Analysis for Different Configurations in Main Profile


Authors: Zoran M. Milicevic, Zoran S. Bojkovic

Pages: 109-112

Abstract: This paper seeks to provide performance analysis for High Efficient Video Coding (HEVC) HM-16.6 reference coder for different resolution test sequences and picture structures. Two test sequences (resolutions) i.e., PeopleonStreet (2560x1600) and ParkScene (1920x1080) are considered. The HEVC coder is tested for the fixed Quantization Parameter (QP) value in intra, lowdelay and randomaccess configurations, with Main profile when I, P and B pictures are processed in I and IBBB formats, respectively. Two different configurations encoder_intra_main and encoder_randomacces_main are tested. Comparisons were performed with respect to the change of Signal-to-Noise Ratio (SNR), the change of data bit-rate and the change of encoding time saving, respectively. Simulation results have shown differences in SNR values for luma component of picture. Beside objective results, subjective video assessments for all tested sequences are presented, too.

Title of the Paper: Transfer and Validation of Adaptive Method for Assessing the Life Expectancy of a Wireless Sensor Network in Smart Environments Applications


Authors: Aleksejs Jurenoks, Viktorija Ponomarenko, Leonids Novickis

Pages: 102-108

Abstract: Technology transfer is a bridge between research organizations and industry. It is an important task to find right way how to present a new technology for the audience. This paper describes the conditions of the distribution of network nodes and determines the basic coefficients that affect the overall life expectancy of a wireless sensor network. The goal of this research is to validate the provided methods for calculating the lifecycle of the main nodes in a wireless sensor network to be transferred to the market. To achieve this goal was applied technology transfer model developed during the Baltic Sea Region INTERREG Program project. First results of validation are presented in this paper.

Title of the Paper: Improving the Delivery Rate of Data with : DTN Routing Hierarchical Topology (DRHT)


Authors: El Arbi Abdellaoui Alaoui, Said Agoujil, Moha Hajar, Youssef Qaraai

Pages: 95-101

Abstract: This paper presents an approach to improve quality of service parameters over a delay tolerant network (DTN), which comprises of multiple message ferries, cluster heads of node clusters, and regular nodes. Intra-cluster routing is done via the mediation of cluster head; inter-cluster routing is done with the help of message ferries. This approach forms a structure capable to adapt dynamically to changes in the mobile environment. We provide also an asynchronous algorithm that will minimize the number of messages replicated and the network resources in general. Finally, we will present the simulation results demonstrating the effectiveness of the topology and routing protocol, particularly for high-density network nodes.

Title of the Paper: A New SLM Technique Based on Genetic Algorithms for PAPR Reduction in OFDM Systems


Authors: Tarik Hadj Ali, A. Hamza

Pages: 91-94

Abstract: Orthogonal Frequency Division Multiplexing (OFDM) technique has been widely adopted in many wireless communication systems due to its high data-rate transmission ability and robustness to the multipath fading channel. One of the major disadvantages of OFDM technique is the high PAPR in the time domain signal. The larger peak-to-average power ratio (PAPR) would cause the fatal degradation of BER performance and undesirable spectrum regrowth. One of the promising PAPR reduction methods is the Selective Mapping method (SLM) which can achieve better PAPR performance without signal distortion. In this paper, a new effective PAPR reduction technique using SLM based on Genetic Algorithm (GA) is proposed. GA is applied to SLM-OFDM system for searching the optimum phase rotation factors and reducing computational burden. The simulation results show that the proposed GA based SLM-OFDM system provides better PAPR reduction compared to conventional SLM-OFDM system.

Title of the Paper: Accuracy Improvement Using WLAN for Indoor Positioning Systems


Authors: Ye Tian, Wenjian Wang, Chang-Jun Ahn

Pages: 86-90

Abstract: At present, the theory and algorithm of wireless indoor positioning systems have been widely researched. Some applications of these systems have been successfully used such as inventory management. Nevertheless, positioning using radio signals indoor is subject to multipath propagation and other causes. Therefore, how to determine the location accurately has been recognized as a difficult task. This paper focuses on one of the positioning methods called received signal strength indication (RSSI) in a Wireless Local Area Network (WLAN). To improve the positioning accuracy, we proposed a scheme which to estimate the distance between access point (AP) and mobile station (MS) using the average of pilot signal strength in frequency domain. We then propose another scheme to estimate the position of the MS utilizing a weighted least-squares (LS) method. At last, the simulations results show that the proposed schemes have a higher degree accuracy compared with the conventional methods.

Title of the Paper: Sphere Mobile Robots for Highly Connected Wireless Multihop Sensor Networks


Authors: Hiroaki Higaki

Pages: 80-85

Abstract: For wireless sensor networks with autonomously mobile sensor nodes, the sensor nodes are required to support both agile mobility and high connectivity. The agile mobility guarantees high observability and the high connectivity realizes high performance wireless multihop transmissions of sensor data. This paper proposes sphere mobile robots with sensor devices which moves any direction without the time overhead for change of mobility direction and with multiple directional antennas to detect mobility of neighbor mobile robots. Based on the change of direction and receipt power of wireless signals from the neighbor mobile robots, each mobile robots find its way to keep connectivity with the neighbor mobile robots. The constitution of the sphere mobile robots and the results of the brief performance evaluation experiments are also discussed.

Title of the Paper: Synthesis of Voltage-Mode All-Pass Filter Employing Single Current Operational Amplifier


Authors: Hasan Çiçekli, Ahmet Gökçen

Pages: 76-79

Abstract: In this paper, a new voltage-mode all-pass filter topology based on single current operational amplifier (COA) and the implementation of COA by using current conveyors are presented. Using the proposed topology, two non-inverting and two inverting all-pass filters can be realized by modifying three admittances. COA implementation by using current conveyor blocks as sub-circuit contributes to workability of the COA employing circuits by using commercially available integrated circuits that can be employed as current conveyor. The validity of the proposed filter is verified by using PSPICE simulation program. Simulation is done for both CMOS based COA using the MOSIS 0.35 micron CMOS process parameters and AD844 based COA using the Spice Macromodel parameters of AD844 by Analog Devices.

Title of the Paper: Study of Software Development in Developing Countries: Case of Croatia


Authors: Nikola Vlahovic, Ljubica Milanovic Glavan, Anja Frankovic

Pages: 67-75

Abstract: High demand for software developers from leading global software development companies has encouraged education of software developers, software architects and programmers all over the world. In developing countries this trend was additionally pronounced as the cost of software experts from developing countries was more competitive in global markets than those of developed countries. Consequently developing countries initiated establishing small but profitable software industries that have shown some remarkable properties during the recent challenging economic fluctuations. The global economic crisis during 2008 and 2009 has resulted in the recessive trends for most industries initiating decline in industrial production and economic expansion. Software industry has proven to be one of the most resilient industries. In this paper we will present the research of key features of software industry in developing countries that makes it resilient to difficult economic fluctuations. Despite their relatively small proportion in overall industrial structure they can be used as a basis for international competitiveness. The goal of this paper is to identify most important structural and organizational features as well as the sources of comparative advantages that empower software companies in global international software markets. For the purpose of this paper research was conducted on the case of Croatia. Research is twofold: Firstly, tructural and economic effects and properties will be analyzed from secondary statistical data about Croatian software companies and secondly, additional survey will be used to explain additional details pertaining to software development approaches and market strategies of these companies. Based on the results software industry structure, market targeting and software evelopment practices are identified and outlined explaining how they contribute to strengthening competitive advantage of small national software industries in developing countries on the global software markets.

Title of the Paper: Medicine Tracing System: Validating a Model at the Largest Hospital Complex in Brazil


Authors: Elcio B. da Silva, Maria L. R. P. Dias, Eduardo M. Dias, Sergio L. Pereira, Vidal A. Z. Melo

Pages: 57-66

Abstract: This paper presents models of medicines track and trace systems adopted over the world, focusing on the Brazilian model, the National Medicines Control System (SNCM), its requirements and peculiarities. Considering the necessity of tracing medicines in compliance with that, the present work proposes a pilot project for the implementation of SNCM in the largest Public Hospital complex in Brazil, Hospital das Cl?nicas (HC). First, it introduces the background of Brazilian track and trace regulation and its impact. Then, it presents models of medicines track and trace systems in five other countries. After that, specific features and challenges of the Brazilian law are presented, leading to a comparison of experiences. After that a pilot project for HC is proposed, highlighting the benefits that will result for the participants, between them compliance and patient security.

Title of the Paper: NARMA Equalizer for Nonlinear ITU Channels with Modified Feedback


Authors: Murchana Boruah, Aradhana Misra, Manash Pratim Sarma, Kandarpa Kumar Sarma, Nikos Mastorakis

Pages: 49-56

Abstract: A Rayleigh fading channel is nonlinear in nature. Therefore channel modeling techniques can be more accurately represented by nonlinear stochastic models. In this paper, we consider a block faded Single Input Single Output (SISO) system. A Nonlinear Autoregressive Moving Average (NARMA) filter is designed to equalize the received signal. A double feedback equalizer structure is employed to make the training of the system more detailed. The effectiveness of this method is validated by simulations. Bit Error Rate (BER) vs. Signal to Noise Ratio (SNR) curve is analyzed for different channel conditions specified by Third Generation Partnership Project (3GPP) standards and International Telecommunication Union (ITU) specifications. Performance is evaluated for different training overheads and a tradeoff between spectral efficiency and performance is obtained. The proposed equalizer structure gives better performance in severe fading environments as well as in a low percentage of training symbols. The entropy is also increased when compared to a single feedback NARMA receiver structure.

Title of the Paper: Adaptive Radio Link Design for Unmanned Aerial Vehicles with M-ary PSK Modulation and Different Coding Schemes


Authors: Amirhossein Fereidountabar, Gian Carlo Cardarilli, Rocco Fazzolari, Luca Di Nunzio

Pages: 39-48

Abstract: Radio channel is one of the most important parts of a communication system. Main elements of a radio links are modulation, coding, number of the transmitter and the receiver antennas that can be only one, SISO (Single Input Single Output) or more than one, MIMO (Multiple Input Multiple Output). In the wireless links one of the problems is Doppler shift and another is fading. The goal in this paper is designing a radio link for Unmanned Aerial Vehicle (UAV) to the ground station. Starting from the description of the model geometry, this paper presents the results of the simulation of the SISO/MIMO channel model and calculates the rays path loss for a site considering the effects of obstacles, scattering and reflecting components. In this paper the number and location of the obstacles are deterministic but the number and the location of scatterer clusters are random. We will try to consider all the propagation elements for evaluating the actual path loss. Later we consider effect of different coding techniques and different schemes of PSK modulation for designing a radio link with minimum outage probability.

Title of the Paper: Enhancing Performance of Multi-Rate WLANs: Hopfield Neural Network Approach


Authors: Qiang Ma, Abdullah Al-Dhelaan, Mznah Al-Rodhaan

Pages: 30-38

Abstract: In a multi-rate 802.11 WLAN environment, the trade-off between users’ fairness and network throughput might be unacceptable. In this paper, we will design a new intuitive mathematical model called simplified coefficient of variation (SCV) model that would closely reflect our topic. SCV could optimize and enhance the trade-off problem through controlling the power of Access Points. Since our topic is a NP-hard problem, we use Hopfield Neural Network solution to solve our SCV model in a practical scenario. The simulation gives excellent results indicating our model is efficient and superior to an existing method through a comparison analysis. In addition, we use software SAS to further reveal the relationships among the three indicators to illustrate the essence of our algorithm and an existing algorithm.

Title of the Paper: An Intelligent Methodology for Malware Detection in Android Smartphones Based Static Analysis


Authors: Ahmed H. Mostafa, Marwa M. A. Elfattah, Aliaa A. A. Youssif

Pages: 21-29

Abstract: Recently, a lot of mobile phone users are rapidly switching to smartphones, and, many users download mobile applications without any thought of security. Therefore, smartphones are interesting target for malware, especially with Android devices. So, it is too important to use a methodology to detect the malware applications before installing it on the phones. In this paper we propose an e?ective methodology to detect Android malware using static code analysis based models. The proposed models are built to extract features relevant to malware based on extracted permissions from AndroidManifest.xml file as well as extracted methods and APIs from disassembled code to be used as features for training machine learning classifiers.

Title of the Paper: Assessment of Menstrual Cycle and Behavioral Changes Using Digital Speech Processing Techniques


Authors: Kavita Thakur, Mohana Roy Chowdhury, Anjali Deshpande, A. S. Zadgaonkar

Pages: 1-20

Abstract: It has been observed that speech can prove to be an important tool for the diagnosis of various physiological parameters. Early use of phonetics in the field of medical study has been reported in 1911 by H. Gutman. With the rapid progress of technology, such techniques are emerging as alternative non-invasive diagnostic tools. Since the onset of menstrual cycle plays a very significant role in the transition of an adolescent female into an adult, it is important to study and monitor the physiological and psychological changes that occur during the cycle. In this work Formant frequency analysis has been carried out, since Formant frequency represent the intricate features of human body. The current techniques used for the diagnosis of hormonal changes are invasive, expensive and require sophisticated laboratory setup, besides being time consuming. In this experiment, we have attempted to study the changes that take place in the quality of speech during the menstrual cycle, with the intention of detecting the hormonal and behavioral changes that occur at the different stages. Further improvement of such techniques should aid in the early diagnosis of fertility based disorders. This method, apart from being non invasive, required no sophisticated laboratory set up, and thus can be used for the diagnosis in rural areas that lack infrastructure.