Telfor Journal Vol.7 No.1 (2015)

Content

Editorial HyperLink
Editor-in-Chief: Prof. Dr Đorđe Paunović

Service Class Mapping based on Integer Programming Algorithm in the Third Party Agent

B. J. Mali, N. M. Ninkovic, M. D. Stojanovic and G. I. Savic
Topic:
Telecommunications Networks
Abstract
In this paper, we propose a novel algorithm for mapping of service classes among multiple Internet providers on an end-to-end (E2E) path. The third-party (3P) approach is assumed for E2E service negotiation, whereas the foundation for class mapping is laid on the integer programming mathematical model. The algorithm selects service classes in domains on the path so that requirements for E2E quality of service (QoS) are fulfilled. This selection is based on multiple constraints, referring to performance fulfillment and at the same time aiming to achieve minimal E2E interconnection cost through definition of a single objective function. Performance evaluation has clearly indicated benefits of the proposed algorithm in terms of QoS achievement and decreasing costs, as well as its suitability for services that require stringent QoS guarantees.
Keywords
Integer programming, Mapping, Negotiation, Quality of service, Third party model.
Full Text
HyperLink Service Class Mapping based on Integer Programming Algorithm in the Third Party Agent
Page(s)
2-7
Doi
10.5937/telfor1501002M

Traffic Prioritisation in 802.15.6 MAC – Analysis of its CSMA/CA Algorithm and Proposals for Improvement

M. Bukvić and J. Mišić
Topic:
Telecommunications Networks
Abstract
This paper focuses on the treatment of uplink traffic of the highest data priority, i.e. Emergency traffic in the 802.15.6 standard for a wireless body area network (WBAN). This standard is one of the choices available for the so-called wearable Internet or wireless connection between electronic devices worn on or implanted in the human body. The features for positive discrimination of emergency traffic are identified at three different components in the 802.15.6 standard in order to emphasize the importance of its prioritized delivery that must be always preserved due to potential applications in the field of monitoring of health variables. However, prioritization could be compromised by the anomaly in the medium access under contention algorithms in standard 802.15.6. That is the reason that we find it appropriate to address the anomaly, i.e. to describe a sequence of packets that can bring a station into the state in which it sends highest-priority data frames with the parameters of the back-off algorithm used for traffic with a significantly lower priority and thus reduces the station’s chances to access the medium. The main contribution of this work is to identify the set of five conditions that must be met at the same time in order to make the anomaly to appear, and explain that the scene for anomaly manifestation would be set up periodically in secured communication. We provide a simulation study and discussion on the available solutions for preventing this anomaly including a minor change to the algorithm at the level of the standard.
Keywords
body area network, CSMA/CA, IEEE 802.15.6, QoS, WBAN.
Full Text
HyperLink Traffic Prioritisation in 802.15.6 MAC – Analysis of its CSMA/CA Algorithm and Proposals for Improvement
Page(s)
8-13
Doi
10.5937/telfor1501008B

Trade-off Analysis of Energy-Efficiency versus Generated Interference when using Regenerative Relay

G. Dimić, Member, D. Bajić, and M. Beko
Topic:
Radio Communications
Abstract
When using a regenerative relay, a trade-off between increasing the energy efficiency versus reducing the generated interference arises. In this paper, the generated interference in the direct link from the base station to a user terminal is compared with the generated interference from both the base station and the relay node in regenerative relay transmissions. In the space of channel losses, in the transceivers' operating region, the lines corresponding to the generated interference ratio comparing the relay scheme and the direct link are depicted. It is shown that it is possible to tune the energy-efficiency vs generated interference trade-off, by adjusting the transmit powers, constellation size and code rate. The trade-off depends on the channel losses along the links. A key enabler of the trade-off is the appropriate placement of the relay node.
Keywords
energy efficiency, hetnets, interference reduction, power control, regenerative relay, wireless.
Full Text
HyperLink Trade-off Analysis of Energy-Efficiency versus Generated Interference when using Regenerative Relay
Page(s)
14-19
Doi
10.5937/telfor1501014D

Software Realization on the MSC nanoRISC Hardware Platform, for Communication according to the IEC61850 Standard

A. V. Kabović, M. M. Kabović, and V. V. Čelebić
Topic:
Communication Systems
Abstract
This paper describes software realization and its implementation for the communication, according to the IEC61850 standard, between the module for monitoring teleprotection devices and the control/monitoring server in a power substation. Teleprotection devices have an important role in the transmission of messages for power line section tripping. The software is implemented on the “MSC nanoRISC-S3C2416 MB2” hardware platform type, which belongs to the COM (computer on module) systems.
Keywords
communication, electric power utility, IEC61850, nanoRISC-S3C2416, substation, software, teleprotection.
Full Text
HyperLink Software Realization on the MSC nanoRISC Hardware Platform, for Communication according to the IEC61850 Standard
Page(s)
20-25
Doi
10.5937/telfor1501020K

Classifying sEMG-based Hand Movements by Means of Principal Component Analysis

M. S. Isaković, N. Miljković, and M. B. Popović
Topic:
Signal Processing
Abstract
In order to improve surface electromyography (sEMG) based control of hand prosthesis, we applied Principal Component Analysis (PCA) for feature extraction. The sEMG data from a group of healthy subjects (downloaded from free Ninapro database) comprised the following sets: three grasping, eight wrist, and eleven finger movements. We tested the accuracy of a simple quadratic classifier for two sets of features derived from PCA. Preliminary results suggest that the first two principal components do not guarantee successful hand movement classification. The hand movement classification accuracy significantly increased with using three instead of two features, in all three sets of movements and throughout all subjects.
Keywords
feature extraction, healthy subjects, grasp, principal component analysis, surface electromyography.
Full Text
HyperLink Classifying sEMG-based Hand Movements by Means of Principal Component Analysis
Page(s)
26-30
Doi
10.5937/telfor1501026I

Evaluation of Kolmogorov - Smirnov Test and Energy Detector Techniques for Cooperative Spectrum Sensing in Real Channel Conditions

D. Lekomtcev and R. Marsalek
Topic:
Signal Processing
Abstract
The cognitive radio technology allows solving one of the main issues of current wireless communication technologies, namely a deficit of vacant spectrum. A dynamic spectrum access used in the cognitive radio networks (CRN) gives an ability to access an unused spectrum in real time. Cooperative spectrum sensing is the most effective method for spectrum holes detecting. It combines sensing information of multiple cognitive radio users. In this paper, an experimental evaluation of spectrum sensing methods based on the Kolmogorov - Smirnov statistical test and Energy Detector using the Universal Software Radio Peripheral (USRP) devices synchronized through a MIMO cable and with further processing in the GNU Radio and Matlab software are presented. Three hard decision fusion schemes are analyzed. Simulation comparison between these rules is presented via Receiver Operating Characteristic (ROC) curves. The influence of real channel with interferences is compared in contrast to commonly assumed AWGN channel model of vacant channel noise.
Keywords
Spectrum sensing, K-S test, Energy Detector, Fusion Rules, Receiver Operating Characteristic (ROC), GNU Radio, USRP, MIMO.
Full Text
HyperLink Evaluation of Kolmogorov - Smirnov Test and Energy Detector Techniques for Cooperative Spectrum Sensing in Real Channel Conditions
Page(s)
31-36
Doi
10.5937/telfor1501031L

A Class of Selective CIC FIR Filter Functions

V. D. Pavlović, D. N. Milić, and B. P. Stošić
Topic:
Signal Processing
Abstract
A new class of modified selective multiplerless Cascaded-Integrator-Comb (CIC) finite impulse response (FIR) filter functions with application in modern communication systems, which have superior performances compared to the classical CIC filter functions are presented here. A few design examples that illustrate the properties of the proposed filter class are also presented. Novel filter functions have a minimum attenuation of 166.52 dB, 258.56 dB and 350.46 dB, respectively. The achieved improvements versus classical CIC filters are 29.84 dB, 34.90 dB and 39.82 dB, respectively.
Keywords
CIC filters, FIR filters, linear phase, multiplierless structure, selective filters.
Full Text
HyperLink A Class of Selective CIC FIR Filter Functions
Page(s)
37-42
Doi
10.5937/telfor1501037P

Phase Space of Tristability in Dual Injection-Locked Fabry-Perot Laser Diodes

R. V. Pajković, M. M. Krstić, J. V. Crnjanski, A. R. Totović, and D. M. Gvozdić
Topic:
Optical Communications
Abstract
We investigate theoretically the case of dual injection-locking, in which the two light signals are simultaneously externally injected into the cavity of a slave Fabry-Perot laser diode. We show that dual injection-locking leads to formation of new stationary points, and potentially to optical tristability of the slave laser. We show that a region in which the slave laser exhibits three stable steady-states occurs only for sufficiently different frequency detunings of the two injection signals. Moreover, the slave laser tunability depends on the choice of injection modes, and strongly depends on the slave laser bias current, with an optimal value around 2 times threshold current.
Keywords
dual injection-locking,Fabry-Perot laser diode, optical bistability, tristability.
Full Text
HyperLink Phase Space of Tristability in Dual Injection-Locked Fabry-Perot Laser Diodes
Page(s)
43-48
Doi
10.5937/telfor1501043P

Towards a Light-weight Bag-of-tasks Grid Architecture

I. Bašičević, N. Četić, M. Popović, and M. Krunić
Topic:
Software Tools and Applications
Abstract
The paper presents the application of SIP protocol in the context of bag-of-tasks grid architecture. The SIP protocol has been used in the realization of the execution management service. The main idea is the use of stateful SIP proxy as a request broker. The paper provides a description of the concept, and the prototype system that has been built, as well as the calculation of estimated performance level and its relation to maximum RTT of grid system. The main advantage of this light-weight grid architecture is the reuse of a mature infrastructure. A short overview of some approaches to the mathematical modeling of computer grids is included.
Keywords
Session Initiation Protocol, grid computing, bag-of-tasks, execution management service, job scheduling.
Full Text
HyperLink Towards a Light-weight Bag-of-tasks Grid Architecture
Page(s)
49-54
Doi
10.5937/telfor1501049B

Implementation of Android application for faculty employees

S. B. Purić, U. P. Romić, and B. D. Nikolić
Topic:
Software Tools and Applications
Abstract
The paper describes the functionality and implementation of applications for mobile phones used in the School of Electrical Engineering at the University of Belgrade in the daily work of faculty employees. The application uses a system’s shared data for financial and material accounting, human resources and teaching process. The system was implemented using a REST Web service, Google's model for Android REST client applications and Robospice technologies.
Keywords
faculty Web services, Android application, Robospice, REST Web services.
Full Text
HyperLink Implementation of Android application for faculty employees
Page(s)
55-60
Doi
10.5937/telfor1501055P