Influence of the call forwarding busy service on the traffic distribution in the group of telephone channels

In this paper we consider the influence of a call forwarding service on the traffic process in modern telecommunication networks. We analyse in detail only the case when the called user is busy. It is proved that call forwarding not only increases utilization of servers and the percent of successful calls but it also increases the call loss. On the simple example, we showed that this call loss increase is greater in the case of local (internal) and incoming calls, but smaller in the case of outgoing calls. The reason for such behaviour is in the role of call forwarding function in the case of internal and incoming traffic. In that situation call forwarding function decreases the effect of limited number of users on the decrease of offered traffic, comparing to the case of internal and incoming traffic without call forwarding (Engset traffic model). This statement is illustrated by comparative graphics of traffic loss without call forwarding function, and with this function when considering, separately, internal, incoming, and outgoing traffic. [Projekat Ministarstva nauke Republike Srbije, br. TR32007: Multiservice optical transport platform with OTN/40/100 Gbps DWDM/ROADM and Carrier Ethernet functionality

An overview and analysis of BER for three diversity techniques in wireless communication systems

Characteristics of a wireless communication channel are subjected to a large scale deterioration process, referred to as the problem of fading. This paper discusses different techniques for mitigating the fading problems. One solution to the problem is to add a fading margin on the transmitter, but it is not an effective solution. The other solution is to use an alternative statistical behavior of fading channels (applying the basic concepts of diversity), which use two or more inputs on the receiver to ensure the correlation of signal. So, the diversity technique is used to improve system performance in fading channels. Instead of transmitting and receiving the desired signal through one channel, we have L copies of desired signal transferred over M different channels. This paper presents analytical results of the probability of error for diversity techniques which use Rayleigh Fading Channel for BPSK modulation

Mobile Banking Authentication Based on Cryptographically Secured Iris Biometrics

This paper presents an approach to designing secure modular authentication framework based on iris biometrics and its’ implementation into mobile banking scenario. The system consists of multiple clients and an authentication server. Client, a smartphone with accompanying application, is used to capture biometrics, manage auxiliary data and create and store encrypted cancelable templates. Bank’s authentication server manages encryption keys and provides the template verification service. Proposed system keeps biometric templates encrypted or at least cancelable during all stages of storage, transmission and verification. As templates are stored on clients in encrypted form and decryption keys reside on bank's authentication server, original plaintext templates are unavailable to an adversary if the phone gets lost or stolen. The system employs public key cryptography and pseudorandom number generator on small-sized templates, thus not suffering from severe computational costs like systems that employ homomorphic encryption. System is also general, as it does do not depend on specific cryptographic algorithms. Having in mind that modern smartphones have iris scanners or at least high- quality front cameras, and that no severe computational drawbacks exist, one may conclude that the proposed authentication framework is highly applicable in mobile banking authentication

Hybrid methodological approach to context-dependent speech recognition

Although the importance of contextual information in speech recognition has been acknowledged for a long time now, it has remained clearly underutilized even in state-of-the-art speech recognition systems. This article introduces a novel, methodologically hybrid approach to the research question of context-dependent speech recognition in human–machine interaction. To the extent that it is hybrid, the approach integrates aspects of both statistical and representational paradigms. We extend the standard statistical pattern-matching approach with a cognitively inspired and analytically tractable model with explanatory power. This methodological extension allows for accounting for contextual information which is otherwise unavailable in speech recognition systems, and using it to improve post-processing of recognition hypotheses. The article introduces an algorithm for evaluation of recognition hypotheses, illustrates it for concrete interaction domains, and discusses its implementation within two prototype conversational agents

10.5937/tehnika1703383L= Development of methods for traffic simulation of telecommunication processes in IRITEL over 45 years

This paper summarizes the programs intended for simulation of traffic processes in different telecommunications systems. These programs are developed, implemented and verified by the members of the Institute IRITEL through numerous scientific papers and doctoral dissertations taken during 50 years of the Institute activities. Two main areas of traffic simulations are related (but not limited) to the analyses of switching systems and mobile telephony systems