Therdpong Daengsi

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This paper presents new evidence about user perception of VoIP quality that is inconsistent with the general understanding of three codecs know as G.729, G.711 and G.722. The focus of the study is aimed at VoIP quality evaluation by Thai users that use the Thai language which is tonal. This study was conducted by using conversation-opinion tests. The(More)
This paper presents a preliminary study of quality of experience (QoE) of VoIP that are provided as social network services using Perceptual Evaluation of Speech Quality (PESQ) with Thai and Chinese speech samples. This study focuses on VoIP quality of the free call feature from Facebook and LINE, which are the popular social network site and the popular(More)
To aid authenticity, accuracy and reliability of subjective measurement of VoIP quality measurements, this paper proposes a model that has been created from the subjective MOS, instead of using existing objective measurement methods for VoIP quality measurement. The proposed model of VoIP quality measurement method is based-on Thai users. The data has been(More)
This paper presents an enhanced objective method for VoIP quality evaluation. However, instead of improving the original E-model for G.729, the Simplified E-model has been enhanced using subjective MOS estimation model based-on Thai users, who used Thai-tonal language. The different results from Simplified E-model and subjective MOS estimation model have(More)
This paper presents a mathematical model that has been created from the subjective MOS, instead of modifying or improving the existing objective measurement methods (e.g., E-model) for VoIP quality measurement. The proposed model of VoIP quality measurement method is based on native Thai users who communicate to each other using Thai language, which is a(More)
This paper presents a study of VoIP - Quality of Experience (VoIP-QoE) of a well-known VoIP application and three modern ones, Skype, LINE, Tango and Viber, using Perceptual Evaluation of Speech Quality (PESQ) with English speech samples. From this study, it has been found that Skype and LINE tend to provide better VoIP quality than Tango and Viber,(More)
This paper presents the conduction of conversational tests with three codecs; G.729, G.711 and G.722 referring to different one-way delays of <;10 ms, 400 ms and 800 ms, to help investigate delay effects to perceived voice quality by Thai users. The result from this study is found that with the best condition of delay (<;10 ms delay), the delay of 400(More)
This paper presents a proposed mathematical model of VoIP quality estimation from G.729. This model is based on native Thai users. The subjective Mean Opinion Score (MOS) were obtained from listening-opinion tests with a total of 102 subjects that covered five conditions of packet loss effects (0%, 3%, 5%, 10% and 20%). The model was then created using a(More)