Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 81 for “"VoIP"”.
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Wireless Network Measurement: VoIP and 802.11e.
… before using it to explore the behaviour of VoIP traffic, using it as a test case to examine the provision of quality of service guarantees via the extended 802.11e MAC. This work is based on several papers [9] [19] [10].
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VoIP packet scheduling for LTE advanced
… are capable of providing Quality of Service for VoIP traffic in a scenario where VoIP and web traffic compete for the same resources. In this study, two sets of algorithms were taken into consideration: QoS differentiated and non QoS differentiated packet scheduling schemes. It is found that …
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Single-ended non-intrusive speech quality monitoring in VoIP
Voice over Internet Protocol (VoIP) is a promising technology and it is expected to replace the traditional telephone networks in the next few years. However, speech quality in VoIP is not guaranteed, due to various new impairments introduced by Internet and Internet Protocol (IP) terminals. …
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The Design of A Multi-party VoIP Conferencing System
… the problems and trade-offs of a multi-party VoIP conferencing system implemented over the Internet and proposes approaches to solve these problems. The current Internet is unreliable, and it degrades the conversational quality of real-time multi-party conferencing. Delay disparities may cause …
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Scaling up VoIP: Transport Protocols and Controlling Unwanted Communication Requests
Millions of people worldwide use voice over IP (VoIP) services not only as cost-effective alternatives to long distance and international calls but also as unified communication tools, such as video conferencing. Owing to the low cost of new user accounts, each person can easily obtain multiple …
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A tool to assess the feasibility of VOIP for contact centres
… benefits could potentially be realized when VOIP is applied in contact centres. However the feasibility of VOIP depends on many factors and makes the evaluation of its feasibility a complex issue. This research proposes an assessment tool to evaluate the feasibility of VOIP in the contact …
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Voice over Internet Protocol (VoIP) : the dynamics of technology and regulation
"What Voice over Internet Protocol (VoIP) is going to do is start to weaken the foundation of the way we've done things for 100 years...Congress already should be discussing the next telecom bill," said Federal Communications Commission (FCC) Chairman Michael Powell in February 2004, before the …
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Implantação de um sistema de telefonia IP em uma rede sem fio: VoIP móvel
… natural da tecnologia de voz sobre IP (VoIP) e a comunicação sem fio, e pode impulsionar o aumento da popularidade da primeira bem como promover constantes avanços da última. Embora seja possível encontrar várias aplicações que oferecem serviço de VoIP na Internet e muitos dispositivos …
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An Algorithm to Evaluate the Echo Signal and the Voice Quality in VoIP Networks
Voice over the Internet Protocol (VoIP) has been increasingly popular, but reliability and voice quality remain important factors that limit the widespread adoption of VoIP systems. Providing good voice quality is of major importance for the transition from the PSTN to VoIP networks. There are …
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Design and evaluation of real-time Voice-Over-IP (VOIP) systems with high perceptual conversational quality
… this thesis we study the design of real-time VoIP (voice-over-IP) systems that can achieve high perceptual conversational quality. The trade-offs in the design and operation of a VoIP system involve the design of speech codecs and strategies for network control, playout scheduling, and loss …
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Impact of Queuing Schemes and VPN on the Performance of a Land Mobile Radio VoIP System
… network is called an LMR Voice over IP (LMRVoIP) system and is a potential solution to the interoperability problem. LMRVoIP systems are time critical, i.e., are delay and jitter sensitive. Transmission of LMRVoIP traffic in a congested packet-switched network with no quality of service …
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Princip hlasové komunikace v IP sítích a její bezpečnost
Tato práce se zaměřuje na technologii VoIP a její zabezpečení. V první části je popsán obecný princip a struktura VoIP systémů a jednotlivé protokoly svázané s VoIP. V další části je rozebráno zajištění kvality služeb a objasněn proces SIP komunikace. V poslední části jsou uvedeny bezpečnostní …
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Analysis and Protection of SIP based Services
… services. IP telephony known as Voice over IP (VoIP) is one of the commercially most important emerging trends in multimedia communications over IP. Due to the flexibility and descriptive power, the Session Initiation Protocol (SIP) is becoming the root of many sessions-based applications such …
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The role of attention-deficit/hyperactivity disorder and parental misperceptions in risk for child physical abuse
Voice over IP (VoIP) is a key enabling technology for the migration of circuit-switched PSTN architectures to packet-based IP networks. However, this migration is successful only if the present problems in IP networks are addressed before deploying VoIP infrastructure on a large scale. One of the …
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System and Methods for Detecting Unwanted Voice Calls
Voice over IP (VoIP) is a key enabling technology for the migration of circuit-switched PSTN architectures to packet-based IP networks. However, this migration is successful only if the present problems in IP networks are addressed before deploying VoIP infrastructure on a large scale. One of the …
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A hybrid and cross-protocol architecture with semantics and syntax awareness to improve intrusion detection efficiency in Voice over IP environments
… in a unified way. Voice over Internet Protocol (VoIP) stands out as the standard that benefits from convergence by carrying voice calls over the packet-switched infrastructure of the Internet. Although sharing the same physical infrastructure with data networks makes convergence attractive in …
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Communication and time distortion
… into acoustic signals that are carried over VoIP connections. The use of actual VoIP connections allows FreeWave to relay its VoIP connections through oblivious VoIP nodes, hence keeping the FreeWave server(s) unobservable and unblockable. When the VoIP channel suffers packet transfer delays, …
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