A methodology for measuring voice quality using PESQ and interactive voice response in the GSM channel designed by OpenBTS

This article discusses a methodology for rating the quality of mobile calls. Majority telecommunications service from the perspective of the whole world is using mobile telephony networks. One of the problems affecting this service and its quality are landscape barriers, which prevent the spread signal. Price and complex construction of classic BTS does not allow their dense distribution. In such cases, one solution is to use OpenBTS technology. Design of OpenBTS is more available, so it can be applied to much more places and more complex points. Purpose of this measurement is a model for effective stations deployment, due to shape and distribution of local barriers that reduce signal power, and thus the quality of speech. GSM access point for our mobile terminals is OpenBTS USRP N210 station. The PESQ method for evaluating of speech quality is compared with the subjective evaluation, which provides Asterisk PBX with IVR call back. Measurement method was taken into account the call quality depending on terminal position. The measured results and its processing bring knowledge to use this technology for more complicated locations with degraded signal level and increases the quality of voice services in telecommunications

IP telephony based danger alert communication system and its implementation

The paper deals with development of a web application allowing to deliver pre-recorded voice messages by using SIP generator. The developed application is a part of complex system, which has been evolved in Dpt. of Telecommunications, Technical University of Ostrava for last three years. Our intent is focused on disaster management, the message, which should be delivered within specified time span, is typed in the application and text-to-speech module ensures its transormation to a speech format, after that a particular scenario or warned area is selected and a target group is automatically unloaded. For this purpose, we have defined XML format for delivery of phone numbers which are located in the target area and these numbers are obtained from mobile BTS's (Base transmission stations). The advantage of this aproach lies in controlled delivery and finally the list of unanswered calls is exported and these users are informed via SMS. In the paper, the core of the danger alert system is described including algorithms of the voice message delivery

Efficient detection of spam over internet telephony by machine learning algorithms

Recent trends show a growing interest in VoIP services and indicate that guaranteeing security in VoIP services and preventing hacker communities from attacking telecommunication solutions is a challenging task. Spam over Internet Telephony (SPIT) is a type of attack which is a significant detriment to the user's experience. A number of techniques have been produced to detect SPIT calls. We reviewed these techniques and have proposed a new approach for quick, efficient and highly accurate detection of SPIT calls using neural networks and novel call parameters. The performance of this system was compared to other state-of-art machine learning algorithms on a real-world dataset, which has been published online and is publicly available. The results of the study demonstrated that new parameters may help improve the effectiveness and accuracy of applied machine learning algorithms. The study explored the entire process of designing a SPIT detection algorithm, including data collection and processing, defining suitable parameters, and final evaluation of machine learning models.Web of Science1013342613341

Centrality evolution of the charged-particle pseudorapidity density over a broad pseudorapidity range in Pb-Pb collisions at root s(NN)=2.76TeV

Peer reviewe

DoS attacks targeting SIP server and improvements of robustness

The paper describes the vulnerability of SIP servers to DoS attacks and methods for server protection. For each attack, this paper describes their impact on a SIP server, evaluation of the threat and the way in which they are executed. Attacks are described in detail, and a security precaution is made to prevent each of them. The proposed solution of the protection is based on a specific topology of an intrusion protection systems components consisting of a combination of Snort, SnortSam and Iptables applications, the solution was verified in experiments. The contribution of this paper includes the performed comparison of the DoS attacks’ efficiency which were tested both without any protection and then with implemented Snort and SnortSam applications as proposed in our solution.Scopus6118417

Data evaluation of the EIA process in accordance with law no. 100/2001 Collection of Law in South Bohemia locality

Categoriation and sorting of several parts of projects is supporting to better orientation in whole information syste

THE CONFLICT SOLUTION BETWEEN OVERBREEDING GREAT CORMORANT IN FISHPOND´S ASEAS CZECH REPUBLIC AND SUSTANIABLE DEVELOPMENT

The cormorant overbreeding is the problem on pan-European scale. The project COST solves this situation based on mutidisciplinary approac

Improvement of network efficiency on the grounds of change communication protocol

This article deals with both theoretical and practical application of Extensible Messaging and Presence Protocol instead of different solution described detailed in the article. It uses periodically HTTP method POST to gain information about a state, which a client stands in. During this process a new connection is created and closed, what enormously makes network traffic mote intensive. Instead of this we used XMPP, this technology eliminates disadvantages of synchronous HTTP connection by its adapting for real time connection. It uses stable connection, what does not need to create it any time any information needs to be sent. It decreased amount of transported data through a network and a time, in which is a client informed about an event due to a fact, that the new solution works in real time

Ökologischer Energetischer Block im betrieb versorgt Pilsen mit grüner energie

This paper describes the opportunity in the energy generation and energy use by the Pilsen heat power station and their positive impact on the environment by the biomass integration for energy generation. Building of this complex took 20 month. It was the equipment, which makes possible to produce the energy from utilization of the biomass. For these reasons, environmental impact is a factor of increasing relevance and importance that conditions the present operation and development of this system and will indisputably have an even more intense effect on the industry in the future

Nowadays technological possibilities of biomass application

The renewable sources have a high priority in national energy concept. However it is important to know that these types of energy cannot fully cover the whole demand of energy given by the primary sources and nuclear energy. Nevertheless it is essential to implement the renewable sources to our power system. The most promising source in the conditions of the Czech Republic is the biomass