“…Their potential to overcome the limitations of keyword-based search in the IR context was soon envisaged, and was explored by several researchers in the SW area (Maedche, Staab, Stojanovic, Studer & Sure, 2003;Guha, McCool & Miller, 2003;Kiryakov, Popov, Terziev, Manov & Ognyanoff, 2004). However, these approaches exhibit certain limitations like: a) the still sparseness of the available SW content (Sabou, Gracia, Angeletou, d'Aquin & Motta, 2007), leading to knowledge incompleteness when applying search to heterogeneous sources of information, b) the poor usability of the systems, specially at the level of query, requiring users to manage complex languages or interfaces to express their information needs, c) the lack of ranking algorithms to cope with large-scale information sources, etc (see Section 2.3). One may say that the undertakings in information search and retrieval from the SW community have not yet taken full advantage of the acquired knowledge, accumulated experience, and theoretical and technical achievements developed through several decades of work in the IR field tradition.…”