Recognizing Voice Over IP: A Robust Front-End for Speech Recognition on the World Wide Web

The Internet Protocol (IP) environment poses two relevant sources of distortion to the speech recognition problem: lossy speech coding and packet loss. In this paper, we propose a new front-end for speech recognition over IP networks. Specifically, we suggest extracting the recognition feature vectors directly from the encoded speech (i.e., the bit stream) instead of decoding it and subsequently extracting the feature vectors. This approach offers two significant benefits. First, the recognition system is only affected by the quantization distortion of the spectral envelope. Thus, we are avoiding the influence of other sources of distortion due to the encoding-decoding process. Second, when packet loss occurs, our front-end becomes more effective since it is not constrained to the error handling mechanism of the codec. We have considered the ITU G.723.1 standard codec, which is one of the most preponderant coding algorithms in voice over IP (VoIP) and compared the proposed front-end with the conventional approach in two automatic speech recognition (ASR) tasks, namely, speaker-independent isolated digit recognition and speaker-independent continuous speech recognition. In general, our approach outperforms the conventional procedure, for a variety of simulated packet loss rates. Furthermore, the improvement is higher as network conditions worsen.Publicad

The diffusion of IP telephony and vendors' commercialisation strategies

This is a post-peer-review, pre-copyedit version of an article published in the Journal of Information Technology. The definitive publisher-authenticated version is available at the link below.The Internet telephony (IP telephony) has been presented as a technology that can replace existing fixed-line services and disrupt the telecommunications industry by offering new low-priced services. This study investigates the diffusion of IP telephony in Denmark by focusing on vendors’ commercialisation strategies. The theory of disruptive innovation is introduced to investigate vendors’ perceptions about IP telephony and explore their strategies that affect the diffusion process in the residential market. The analysis is based on interview data collected from the key market players. The study's findings suggest that IP telephony is treated as a sustaining innovation that goes beyond the typical voice transmission and enables provision of advanced services such as video telephony

Collective bargaining centralisation against all odds? The Italian telecommunications industry after market liberalization

The widespread trends towards markets liberalisation, decline in trade union power, and flexible work organization were expected to push collective bargaining institutions to converge to a decentralised bargaining structure. This crude version of the neoliberal convergence thesis, however, was not borne out. Instead, change in employment relations has been more nuanced than initially thought. This paper explores the conditions under which centralisation of bargaining is possible, even in a more competitive environment with pressures for greater flexibility. It draws on case study evidence from the Italian telecommunications industry, tracing back the process of liberalisation since the early 1990s. It is shown how the strategies and the coalitions between organised labour, business and the state explain in large part this path of institutional change