“…Originally, only low-level information on the operations of the web resources (such as the basic interface details like method names, types and parameters) was available, or non-functional criteria such as response time or usage data (Birukou et al, 2007); Al-Masri and Mahmoud, 2007). The development of registries based on standards such as UDDI allowed the addition of metadata-based techniques (Dong et al, 2004;Chukmol, 2008;Crasso et al, 2008), initially based on traditional keyword search but eventually considering more advanced IR techniques (Plebani and Pernici, 2009) and, in line with the priorities of our work, a more user-oriented view (Rong and Liu, 2010), explicitly based on requirements (Hao and Zhang, 2007;Hao et al, 2010;Nazir et al, 2008). (Skoutas et al, 2010) also bases the discovery of web services on the requirements and, ranks and clusters the relevant services with objective measures based on dominance relationships among them.…”