Telfor Journal Vol.14 No.1 (2022)

Content

Editorial HyperLink
Editor-in-Chief: Prof. Dr Aleksandar Nešković

Evaluation of Reactive Service Function Path Discovery in Symmetrical Environment

M. Mihaeljans and A. Skrastins
Topic:
Telecommunications Networks
Abstract
In this paper we continue our study of path discovery process for Service Function Chaining (SFC) in Software Defined Network (SDN). By default, service function (SF) paths are established proactively - before data transmission takes place. We have argued that this constraint can be eliminated with the use of our proposed Reactive SF path discovery approach. Such SFs as network address translation (NAT) or stateful firewall (FW) are SF path’s symmetry dependent requiring a visit of both ingress and egress flows. Thus, we evaluated SF path discovery processes in Mininet emulation network. Outcome of this study is a comparison of proactive and reactive SF path discovery processes for both asymmetrical and symmetrical SF paths. It shows that even in symmetrical environment reactive SF path discovery has a higher probability of successful SF path detection.
Keywords
Network Service Header, Network function, Packet encapsulation, Symmetrical connection, Software Defined Network, Service Function Chaining.
Full Text
HyperLink Evaluation of Reactive Service Function Path Discovery in Symmetrical Environment
Page(s)
2-7
Doi
10.5937/telfor2201002M

Prototype Wireless Network for Internet of Things based on DECT Standard

I. V. Sinyavskiy, I. M. Sorokin, and A. M. Sukhov
Topic:
Telecommunications Networks
Abstract
This paper presents a software prototype of a wireless network for the Internet of Things (IoT) based on the DECT (Digital Enhanced Cordless Telecommunication) standard. It proposes an architecture for encapsulating commands from the most common IoT protocol, MQTT (Message Queuing Telemetry Transport), into SIP (Session Initiation Protocol) packets. A module is created to embed MQTT-SN (MQTT for Sensor Networks) packets into SIP packets. The module is developed in Go language using the built-in "net" library. Delivery of MQTT-SN packets to IoT devices is carried out using the SIP protocol. Source codes and instructions for installing the gateway can be found at https://github.com/iSinyavsky/mqtt-sn-sip-gateway.
Keywords
DECT for IoT, encapsulation of IoT command, MQTT over SIP, SIP routing.
Full Text
HyperLink Prototype Wireless Network for Internet of Things based on DECT Standard
Page(s)
8-11
Doi
10.5937/telfor2201008S

Design, Implementation and Experimental Testing of a Hybrid Power Supply of Remote Measuring Station in the Surveillance, Alert & Warning System (SAWS)

Ž. V. Despotović and M. Tajdić
Topic:
Applied Electronics
Abstract
The paper presents the design, implementation and experimental testing of a hybrid power supply of telecommunication and measuring equipment incorporated in remote measuring stations, which are an integral part of the global Surveillance, Alert & Warning System (SAWS) in the Republic of Serbia. In these systems, it is very important to provide autonomy of permanent, reliable and quality power supply. In this case, the power supply system is in effect based on the use of solar energy i.e., photovoltaic (PV), in combination with the mains power supply 230V, 50Hz. Solar power is the primary source of power during the day, while in night conditions the secondary power supply is a distribution power grid (more precisely, the distribution power which is used for supplying the night street lighting). This hybrid power system is realized with two controlled chargers (MPPT solar and mains with input power factor correction), battery bank 12V/110Ah with the corresponding system for its monitoring and secondary DC/DC power converters for supplying telecommunication and measuring electronic modules. The key implementation and experimental results obtained during the realization of a SAWS remote measuring station on the river Ub (municipality of Ub), will be presented in the paper.
Keywords
Hybrid power, power electronics, solar energy, MPPT charger, remote measuring, telecommunication.
Full Text
HyperLink Design, Implementation and Experimental Testing of a Hybrid Power Supply of Remote Measuring Station in the Surveillance, Alert & Warning System (SAWS)
Page(s)
12-19
Doi
10.5937/telfor2201012D

Implementation Aspects of Radio Spectrum Monitoring and Surveillance System in the VHF/UHF Frequency Band

V. B. Marinković-Nedelicki, J. D. Radivojević, P. M. Petrović, and A. V. Lebl
Topic:
Radio Communications
Abstract
The radio system for very/ultra high frequency (VHF/UHF) spectrum monitoring and signal processing used in direction finding is presented in this paper. This main system function is based on the implementation of a 6-channel VHF/UHF radio signal receiver. The multicoupler unit allows selection of the desired signal frequency band for the analysis in the receiver. The system implementation is verified according to the user requirements. Several measured electrical characteristics of multicoupler unit and receiver are presented just to illustrate their possibilities for the full application. Besides, the menus for both devices management are briefly described.
Keywords
radio surveillance, VHF/UHF receiver, multicoupler unit, direction finding, electrical characteristics.
Full Text
HyperLink Implementation Aspects of Radio Spectrum Monitoring and Surveillance System in the VHF/UHF Frequency Band
Page(s)
20-25
Doi
10.5937/telfor2201020M

Logical Framework of Information Technology: Systematization of Software Development Research

D. Sa’adillah Maylawati and M. A. Ramdhani
Topic:
Software Tools and Applications
Abstract
This article aims to present a comprehensive Logical Framework for Information Technology (IT) Research, specifically for developing customized IT applications or software. The methodology of writing this article uses a content analysis with the main source of literature review, Focus Discussion Group, and also based on the experience and knowledge of the authors as lecturers of Software Engineering and Software Project Management. This article shows that although current IT development approaches or methodologies (especially software development methodology) continue to develop, good IT design is carried out through six main stages, namely planning, analysis, design, construction, implementation, and maintenance. The success of IT implementation depends on the good process of all stages of IT design. The involvement of all actors/ stakeholders in IT design is essential to be accommodated at all stages of IT design. Quality also becomes the main goal and controls every process of IT development.
Keywords
information technology, logical framework, software development, software engineering, software measurement, software metrics, software project, software quality.
Full Text
HyperLink Logical Framework of Information Technology: Systematization of Software Development Research
Page(s)
26-32
Doi
10.5937/telfor2201026S

Event-based Approach for Analyzing and Designing System: A Case Study of Designing Curriculum System

Y. Andriyani, A. Aminuddin, E. Mahdiyah, and R. Ario Nugroho
Topic:
Software Tools and Applications
Abstract
Designing a system is an important step in the software development process. A use case diagram (UCD) and a class diagram (CD) are the most used diagrams in designing a system. This case study aims to explore the implementation of an event-based approach using the event table (ET) to design the Outcome-based Education Curriculum System (OBECS). In generating a UCD of OBECS, the event-based approach involves three processes: (1) identifying actors and the relationship between actors; (2) identifying use cases and the relationships of the use cases; and (3) generating UCD. Meanwhile, there are four processes in the event-based approach which can be used to generate a CD of OBECS namely: (1) identifying the classes for each event or action using the ET;(2) identifying the relationships between sources and objects; (3) identifying the class’ attributes and methods; and (4) integrating all classes. Our study proposes a clear and simple concept to generate a UCD and CD in designing a system. It is expected that the result of the current study could help a software designer in modelling the system from the system requirement.
Keywords
Class diagram, Design System, Event, Event Table, System Requirements, Use Case Diagram.
Full Text
HyperLink Event-based Approach for Analyzing and Designing System: A Case Study of Designing Curriculum System
Page(s)
33-38
Doi
10.5937/telfor2201033A

Compact Two-position Phase Shifter

D. A. Letavin
Topic:
Applied Electromagnetics
Abstract
The paper proposes and investigates the topology of a phase shifter based on a directional coupler. The dimensions of such a device are reduced by using artificial transmission lines instead of quarter-wave sections. By connecting several pairs of phase-shifting cells instead of the usual one, it was possible to obtain a phase shifter design with two phase shifts (instead of one).
Keywords
Key words or phrases in alphabetical order, separated by commas.
Full Text
HyperLink Compact Two-position Phase Shifter
Page(s)
39-43
Doi
10.5937/telfor2201039L

Potential to use Microstrip Patch Instead of Dipole Antennas in 2.4 GHz Wireless Sensor Networks

M. M. Milivojčević, N. D. Tolić, and M. I. Štimac
Topic:
Applied Electromagnetics
Abstract
This paper describes the process of designing, simulating and measuring antenna parameters in order to perform a comparative analysis of the performance of microstrip patch antennas and dipole antennas intended for use in wireless sensor networks. The implemented antennas are designed for the unlicensed ISM band of 2.402-2.480 GHz as one of the most widely used bands for this type of network. The patch antenna was created based on calculation and tested in simulation software, and then adjusted with appropriate measurements to suit the intended purpose. Measurements in real conditions were made to compare the patch and dipole antennas in the same frequency range. The patch antenna was further tested, due to the specificity of the implementation within the WSN, in an enclosed and open enclosure made of a conductive material that simulates the enclosure of wireless sensor network nodes in certain applications. The aim of this paper is to show the possibility of using patch antennas instead of dipole antennas in the enclosures of wireless sensor networks nodes.
Keywords
Antenna, patch antenna, dipole antenna, wireless sensor networks, ISM band, WSN.
Full Text
HyperLink Potential to use Microstrip Patch Instead of Dipole Antennas in 2.4 GHz Wireless Sensor Networks
Page(s)
44-48
Doi
10.5937/telfor2201044M