Learn More
In two closely related papers we present POLQA (Perceptual Objective Listening Quality Assessment), the third generation perceptual objective speech quality measurement algorithm, standardized by the International Telecommunication Union (ITU-T) as Recommendation P.863 in 2011. This measurement algorithm simulates subjects that rate the quality of a speech(More)
The paper presents a parameter-based model for predicting the perceived quality of transmitted video for IPTV applications. The core model we derived can be applied both to service monitoring and network or service planning. In its current form, the model covers H.264 and MPEG-2 coded video (standard and high definition) transmitted over IP-links. The model(More)
In this paper, we identify quality dimensions which are relevant for speech communication services, such as mobile telephony or Voice-over-IP. These include dimensions perceived when listening to degraded speech, talking against echoes, double-talk capabilities, interacting with delay, conversing over channels with time-varying characteristics, and(More)
We present a method to estimate the perceived listening quality by a subscriber at the end of a common voice telephony conversation. This method was recently introduced in ETSI STQ mobile and was approved as TR 102 506 ‘Speech Quality per Call’ [1]. The idea is to calculate this “speech-quality-per-call” value based on short-term listening quality scores(More)
In two closely related papers we present POLQA (Perceptual Objective Listening Quality Assessment), the third generation perceptual objective speech quality measurement algorithm, standardized by the International Telecommunication Union (ITU-T) as Recommendation P.863 in 2011. The algorithm is composed of two separate parts, a temporal alignment that finds(More)
In our present study we used preparations from Xenopus laevis lungs to perform electrophysiological Ussing chamber measurements, unidirectional flux measurements, and employed molecular approaches to elucidate the presence and function of a cystic fibrosis transmembrane conductance regulator (CFTR) homolog in this tissue. Application of different CFTR(More)
Pulmonary epithelia of air-breathing vertebrates are covered by a thin, fluid layer that is essential for immune defense and gas diffusion. The composition of this layer is maintained by ion transport mechanisms, including Cl(-) transport. The present study focuses on the function of basolateral Cl(-) channels in Xenopus pulmonary epithelia, since knowledge(More)
A thin liquid layer covers the lungs of air-breathing vertebrates. Active ion transport processes via the pulmonary epithelial cells regulate the maintenance of this layer. This study focuses on basolateral Cl(-) uptake mechanisms in native lungs of Xenopus laevis and the involvement of the Na(+)/K(+)/2 Cl(-) cotransporter (NKCC) and HCO(3)(-)/Cl(-) anion(More)