The SARS-CoV-2 (COVID-19) pandemic has emerged as one of the greatest problems of the 21st century worldwide. Efforts to fight this pandemic require a global co-operation and a multidisciplinary approach. An application of information and communication technologies (ICT) to a great degree contributes to fighting the pandemic as these technologies are one of the key services that assist patients, researchers, health institutions and other interested parties in different activities in an effort to fight the pandemic and its consequences. The present paper presents the features of certain mobile applications (apps) that are being used for different purposes such as: tracking patients, COVID-19-related warnings, keeping tracks of statistical data, organising life and business, etc. Aside from presenting the features of a certain number of applications, a review of technologies used for the development of these applications will also be presented. Furthermore, the paper addresses certain challenges that come along with the mobile technologies applications and offers suggestions for future research.

This paper depicts a practical implementation of business model created by Centre for digital communications with customers of ALBA company and the framework of using cloud system in supporting that model. Software implementation includes Web and mobile applications for customers as well as control panel for software administration by company employees. The uniqueness of the implementation is reflected in the advanced geolocation services that include the generation of content according to the user needs based on the selected location of the city or settlements. The model also includes opportunities for further development with the use of IoT technologies to manage the waste disposal process.

Home installation is the shortest segment of FTTH (Fibre to The Home) networks. Despite this, it can also be a bottleneck of the whole network. This segment can produce a huge attenuation of optical signal. This paper deals with attenuation loss in home installations especially because of micro bending and attenuation of fusion splices caused by incompatibility of different fibre types.

The main aim of this paper is to analyse correlation between adjacent images in a video sequence. Adjacent images with a slow or fast changeable scene in a video have high correlation which shows consistency in the video sequence therefore it can be the proof of normal reproduction of video service. Due to QoS (Quality of service) problems, especially over lossy network, appearance of different visual degradations in frames (images) during delivery of video service to end users can happen very often. In that case, adjacent images in the video sequence have low correlation which can be used as an indicator the problem occurred in some part of the network. In addition, the paper analyses correlation correspondent to polygons i.e. parts of adjacent images in the video sequence in order to discover a degree of influence visual degradations to user’s QoE (Quality of Experience). In order to check this aim, tested degraded and non-degraded video sequence was captured using IPTV system of one significant market power provider and processed in offline mod with Python script created especially for this purpose.

This paper presents some results of research of reliability of using simple and low-cost Android-based handheld measurement units for DSL (Digital Subscriber Line) loop qualification a nd/or t roubleshooting. T he g oal o f t his p aper is provide the answer on key question whether such units can be used (and if so, under what circumstances) for quick and reliable evaluation of copper local loop properties, in respect to its ability for exploitation in certain DSL applications. A particular unit has been observing in several typical loop conditions (good loop, fault loop, etc.). Collected results were compared with those obtained from professional measurement equipment. It is shown that simple unit is more unfavourable to use compared to the professional one, in respect to determination of system actual performance. All results of measurements and observations are collected on real system in operation conditions.

The aim of this paper is comparing a simulation model with real IPTV (Internet Protocol TeleVision) scenario in access network. In real IPTV scenarios, it is known that packet losses appear suddenly and might have an "explosive" character, especially in DSL (Digital Subscriber Line) case. In addition, these packet losses usually appear in groups and lead to huge degradation of the video service, which decreases customer’s QoE (Quality of Experience) level. Hence, estimation of this degradation in access network is important and the paper explained one simulation model based on SSIM (Structural Similarity Index) analysis, which can be used as one perceptive video quality assessment by imitating a real environment with packet losses. To check this, we compared our simulation model with the real IPTV video distributed over DSL (Digital Subscriber Line) and exposed to different packet loss appearances.

During delivery of video service, most of management control systems are able to collect useful data from different OSI layers that help in indication quality of video service. Recently, a mathematical model has been proposed which, only with a help of data collected at PHY (physical) and MAC (Media Access Control) layers and after appearance of certain degradations in transmission channel, estimates QoS (Quality of Service) indicators and then objective QoE (Quality of Experience). In this paper, we analyse that mathematical model, but only in the case of sudden occurrence of significant disturbance in transmission channel. In addition, we have chosen AIC criterion instead of the vector one in order to define the size of L-value. Validation and verification of the model are done in DSL (Digital Subscriber Line) environment during IPTV (Internet Protocol Television) service delivering and NS2 respectively.

This paper, on the basis of experimental research of the system in exploitation, identifies the main disadvantages of the existing troubleshooting scenarios for IPTV over xDSL. Also, this paper shows how the process of troubleshooting can be made more efficient in practice, with the already existing test solutions and other possibilities of test devices and xDSL transceivers.

This paper presents an extension of research scope of the relationship between quality of service (QoS) and quality of experience (QoE), which is based on contribution of lower open system interconnection layers, such as physical and media access control, in overall QoS/QoE paradigm. Degradations that inevitably occur in transmission channel are an important reason for appearance of QoS distortion and therefore low values of video quality. Various channel quality indicators (CQIs) relating to domain of communication channel can be used for notification of different interferences in the channel. In order to extend the relationship between QoS and QoE to the transmission channel, the paper proposed the mathematical model that used CQI to estimate values of QoS indicators by using statistical analysis. The model was also expanded by objective video quality metrics in order to evaluate QoE. Verification of the model was checked by experimental method with consideration of Internet protocol television (IPTV) service delivery in Digital Subscriber Line network.

This paper aims to consider how changes in QoS (Quality of Service) indicators affect the quality of IPTV (Internet Protocol Television) video. Degradation of QoS indicators can occur at any point in time, when the value of transfer channel function changes or if there is an appearance of additional noise. Therefore, for this purpose it is necessary to conduct a temporal analysis of the impact of the QoS indicator degradation on the delivery of MM (Multimedia) service in real time. Also, the phenomenon of degradation of QoS can be associated with queues, flow control or with analog-to-digital conversions that occur on the network elements. The combination of all these phenomena in the higher layers of the OSI (Open System Interconnection) reference model can be identified as packet loss, delay or jitter, and this paper examines their impact on the level of video perception by the end consumer. That perception can be identified as QoE (Quality of Experience).

This paper will consider an estimator which includes mathematical modelling of physical channel parameters as information carrier and the weakest links in the telecommunication chain of information transfer. It will also identify necessary physical layer parameters which influence the quality of multimedia service delivery or QoE (Quality of Experience). With the modelling of the above mentioned parameters, the relation between degradations will be defined which appear in the channel between the user and the central telecommunication equipment with domination of one media used for information transfer with certain error probability. Degradations in a physical channel can be noticed by observing the change in values of channel transfer function or the appearance of increased noise. Estimation of QoE IPTV (Internet Protocol Television) service is especially necessary during delivery of real time service. In that case the mentioned degradations may appear in any moment and cause a packet loss.

This paper considers estimation of QoE (Quality of experience), which depends on QoS (Quality of Service) and correlates with it, as well as monitors QoS parameters in lower OSI layers. It also suggests a model that evaluates QoE in different time intervals during consuming of IPTV service under strong influence of non-stationary noise in OFDM (Orthogonal Frequency-Division Multiplexing) modulation scheme.

This paper discovers what parameters of data link layer can be tracked to find relation between QoE (Quality of Experience) and QoS (Quality of Service). It also introduces a new paradigm that relates to consideration of parameters of QoS at all layers of OSI (Open System Interconnection) reference model, and their influence on QoE of end users. In order to analyse relation between data link layer parameters and QoE, the paper presents modification of IQX hypothesis (exponential interdependency of quality of experience and quality of service) in consideration with the mentioned parameters and time. As an example IPTV (Internet Protocol Television) scenario is shown.

This paper compares the values of data link layer QoS (Quality of Service) indicators of several access lines, which can serve as a measure of the physical link quality or QoPh (Quality of Physical Layer), in real environment without reference video signal (No Reference), during the delivering of IPTV (Internet Protocol Television) multicast services to multiple users. It also focuses on the fact that an increase in channel capacity reduces the number of signal degradation indicators in the data link layer, because it increases the resistance of useful information on the interference. The paper proves the fact that at the same time, improving the physical layer conditions, the values of network QoS indicators, such as packet loss or delay, is reduced which affects the final grade at the end-user QoE (Quality of Experience) of IPTV (Internet Protocol Television) services.