Quality aspects of Internet telephony

Internet telephony has had a tremendous impact on how people communicate. Many now maintain contact using some form of Internet telephony. Therefore the motivation for this work has been to address the quality aspects of real-world Internet telephony for both fixed and wireless telecommunication. The focus has been on the quality aspects of voice communication, since poor quality leads often to user dissatisfaction. The scope of the work has been broad in order to address the main factors within IP-based voice communication. The first four chapters of this dissertation constitute the background material. The first chapter outlines where Internet telephony is deployed today. It also motivates the topics and techniques used in this research. The second chapter provides the background on Internet telephony including signalling, speech coding and voice Internetworking. The third chapter focuses solely on quality measures for packetised voice systems and finally the fourth chapter is devoted to the history of voice research. The appendix of this dissertation constitutes the research contributions. It includes an examination of the access network, focusing on how calls are multiplexed in wired and wireless systems. Subsequently in the wireless case, we consider how to handover calls from 802.11 networks to the cellular infrastructure. We then consider the Internet backbone where most of our work is devoted to measurements specifically for Internet telephony. The applications of these measurements have been estimating telephony arrival processes, measuring call quality, and quantifying the trend in Internet telephony quality over several years. We also consider the end systems, since they are responsible for reconstructing a voice stream given loss and delay constraints. Finally we estimate voice quality using the ITU proposal PESQ and the packet loss process. The main contribution of this work is a systematic examination of Internet telephony. We describe several methods to enable adaptable solutions for maintaining consistent voice quality. We have also found that relatively small technical changes can lead to substantial user quality improvements. A second contribution of this work is a suite of software tools designed to ascertain voice quality in IP networks. Some of these tools are in use within commercial systems today

Novel Approach for IP-PBX Denial of Service Intrusion Detection Using Support Vector Machine Algorithm.

Recent trends have revealed that SIP based IP-PBX DoS attacks contribute to most overall IP-PBX attacks which is resulting in loss of revenues and quality of service in telecommunication providers. IP-PBX face challenges in detecting and mitigating malicious traffic. In this research, Support Vector Machine (SVM) machine learning detection & prevention algorithm were developed to detect this type of attacks Two other techniques were benchmarked decision tree and Naïve Bayes. The training phase of the machine learning algorithm used proposed real-time training datasets benchmarked with two training datasets from CICIDS and NSL-KDD. Proposed real-time training dataset for SVM algorithm achieved highest detection rate of 99.13% while decision tree and Naïve Bayes has 93.28% & 86.41% of attack detection rate, respectively. For CICIDS dataset, SVM algorithm achieved highest detection rate of 76.47% while decision tree and Naïve Bayes has 63.71% & 41.58% of detection rate, respectively. Using NSL-KDD training dataset, SVM achieved 65.17%, while decision tree and Naïve Bayes has 51.96% & 38.26% of detection rate, respectively.The time taken by the algorithms to classify the attack is very important. SVM gives less time (2.9 minutes) for detecting attacks while decision tree and naïve Bayes gives 13.6 minutes 26.2 minutes, respectively. Proposed SVM algorithm achieved the lowest false negative value of (87 messages) while decision table and Naïve Bayes achieved false negative messages of 672 and 1359, respectively

ACUTA Journal of Telecommunications in Higher Education

This Is Issue Voice over lP: Still Emerging After All These Years Unified Messaging: A Killer App tor lP State-of-the-Art Communications at SUNY Upstate Medical OptlPuter Enables More Powerful Collaborative Research Wireless Technology: A Major Area of Telecommunications Growth Ready for Convergence: lT Management and Technologists Innovation Culture Clashes Speech Recognition Solves Problems Interview President\u27s Message From the Executive Directo

Pseudo-Separation for Assessment of Structural Vulnerability of a Network

Based upon the idea that network functionality is impaired if two nodes in a network are sufficiently separated in terms of a given metric, we introduce two combinatorial \emph{pseudocut} problems generalizing the classical min-cut and multi-cut problems. We expect the pseudocut problems will find broad relevance to the study of network reliability. We comprehensively analyze the computational complexity of the pseudocut problems and provide three approximation algorithms for these problems. Motivated by applications in communication networks with strict Quality-of-Service (QoS) requirements, we demonstrate the utility of the pseudocut problems by proposing a targeted vulnerability assessment for the structure of communication networks using QoS metrics; we perform experimental evaluations of our proposed approximation algorithms in this context

What Audacity! Decreasing Student Anxiety while Increasing Instructional Time

Promoting student engagement in the second language classroom can be difficult for teachers. Multiple obstacles such as perceptions of the irrelevance of authentic language applications and the affective barriers (e.g. performance anxiety speaking before peers) tend to hinder student oral language performance. For teachers, especially for beginners, other obstacles appear such as being given the most challenging assignments with little to no professional support. Many times these educators scramble to squeeze the most out of every minute in the classroom for instructional purposes while trying to increase student achievement. Three free and open source software options are presented and findings from two studies of focusing on the use of Audacity indicate multiple benefits for both teachers and students. Afterwards, the authors demonstrate how to use Audacity for oral language assessment and discuss its implications for the world language classroom

ACUTA Journal of Telecommunications in Higher Education

This Is Issue Voice over lP: Still Emerging After All These Years Unified Messaging: A Killer App tor lP State-of-the-Art Communications at SUNY Upstate Medical OptlPuter Enables More Powerful Collaborative Research Wireless Technology: A Major Area of Telecommunications Growth Ready for Convergence: lT Management and Technologists Innovation Culture Clashes Speech Recognition Solves Problems Interview President\u27s Message From the Executive Directo

Design and initial validation of the Raster method for telecom service availability risk assessment

Crisis organisations depend on telecommunication services; unavailability of these services reduces the effectiveness of crisis response. Crisis organisations should therefore be aware of availability risks, and need a suitable risk assessment method. Such a method needs to be aware of the exceptional circumstances in which crisis organisations operate, and of the commercial structure of modern telecom services. We found that existing risk assessment methods are unsuitable for this problem domain. Hence, crisis organisations do not perform any risk assessment, trust their supplier, or rely on service level agreements, which are not meaningful during crisis situations. We have therefore developed a new risk assessment method, which we call RASTER. We have tested RASTER using a case study at the crisis organisation of a government agency, and improved the method based on the analysis of case results. Our initial validation suggests that the method can yield practical results

Measuring internet activity: a (selective) review of methods and metrics

Two Decades after the birth of the World Wide Web, more than two billion people around the world are Internet users. The digital landscape is littered with hints that the affordances of digital communications are being leveraged to transform life in profound and important ways. The reach and influence of digitally mediated activity grow by the day and touch upon all aspects of life, from health, education, and commerce to religion and governance. This trend demands that we seek answers to the biggest questions about how digitally mediated communication changes society and the role of different policies in helping or hindering the beneficial aspects of these changes. Yet despite the profusion of data the digital age has brought upon us—we now have access to a flood of information about the movements, relationships, purchasing decisions, interests, and intimate thoughts of people around the world—the distance between the great questions of the digital age and our understanding of the impact of digital communications on society remains large. A number of ongoing policy questions have emerged that beg for better empirical data and analyses upon which to base wider and more insightful perspectives on the mechanics of social, economic, and political life online. This paper seeks to describe the conceptual and practical impediments to measuring and understanding digital activity and highlights a sample of the many efforts to fill the gap between our incomplete understanding of digital life and the formidable policy questions related to developing a vibrant and healthy Internet that serves the public interest and contributes to human wellbeing. Our primary focus is on efforts to measure Internet activity, as we believe obtaining robust, accurate data is a necessary and valuable first step that will lead us closer to answering the vitally important questions of the digital realm. Even this step is challenging: the Internet is difficult to measure and monitor, and there is no simple aggregate measure of Internet activity—no GDP, no HDI. In the following section we present a framework for assessing efforts to document digital activity. The next three sections offer a summary and description of many of the ongoing projects that document digital activity, with two final sections devoted to discussion and conclusions