1504 J. Serrano-Guerrero et al Information Sciences 181 (2011)1503-1516 nformation 2.0 N-way information ow Nonlinear Participatory Interactive Librarian 2.0 Collaborative Fig. 1. Library 2.0. development of new technologies has allowed the appearance of new paradigms: this is the case of Web 2.0 and conse- quently the appearance of Library 2.0. o The first person who used the term Web 2.0 was Dale Dougherty from the company O Reilly Media in 2004 and from that oment, Tim O'Reilly [37] started to use that term in his conferences to refer to the new developments that the Web The precise definition of Web 2.0 is not clear. Many definitions can be found but the researchers are still discussing the definitive definition. It is not clear if the Web 2.0 is a new paradigm or simply a natural evolution of the current Web. Web 2.0 is based on the user as the main figure who is capable of creating, modifying and publishing the content of the Web pages in collaboration with other users. The user is able to interact in simplified way with the applications because they are very lightweight, and it is not required to be an expert in computer science to write your own content in applications such as blogs, wikis, social networks, etc. Many new services 2.0 are appearing everyday: Facebook, Flickr, Wikipedia and Blogspot are some clear examples of this fact. The continued development of new and innovative applications involves the appearance of new paradigms, such as in the case of Google Wave, a new tool which is capable of encapsulating typical functions from other Web applications such as RSS, blogs, chats, wikis, social networks, etc. The application of the capabilities of this new technology to the UDLs is one he objectives of this work in order to extend the concept of Library 2.0. The first person who used the term Library 2.0 was Casey [12] and since that moment many related works have emerged [15,48, 50. Xu 51 depicted a model (see Fig. 1)of the Library 2.0 based on three components, (i)the information. (ii) the users and (iii)the librarians. He summarizes several applications based on Web 2.0 tools(blogs, RSS, tagging, wikis, social networks, and podcasts) applied to Academic libraries and this is the objective of this work as well, the application of the Google wave technology to develop a recommender system that will suggest users and digital resources for collaborative purposes between the users of a University Digital Library, specially the researchers. This system allows the reduction of the necessary time to find col- laborator and information about digital resources depending on the user needs. An example of an application of the system would be when several research groups want to request a European project. These research groups have decided to collaborate for research purposes and they request a common environment(a wave) from the university staff. They are the first members of the wave and for example the official announcement and other re- lated documents are the first resources of the wave but it is necessary to find new partners and old documents about the announcements from past years, etc. That is the moment in which the recommender system suggests and relevant resources from the library to achieve the collaborative objectives of the wave. The proposed recommender system is mainly based on Fuzzy Logic [18, 21] which has been used successfully in other pre- vious approaches [14, 23, 40, 41 The rest of the paper is organized as follows. Section 2 presents the preliminaries of this work: Google Wave, Recom- lender Systems and Fuzzy Linguistic Modeling. Section 3 presents the architecture and the main characteristics of the pro- posed fuzzy linguistic recommender system. Section 4 presents the results of an experiment using this system and finally ome conclusions and future works are pointed out. 2. Foundations 2.1. Google wave Web 2.0 proposes the use of many new applications with collaborative purposes, now the interaction between users is one of the main points of the information and communication technologies. Following this idea google wave has introduced a new communication and collaboration platform built around hosted conversations called waves. The wave model enables https://wavegoogle.comdevelopment of new technologies has allowed the appearance of new paradigms; this is the case of Web 2.0 and conse￾quently the appearance of Library 2.0. The first person who used the term Web 2.0 was Dale Dougherty from the company O’Reilly Media in 2004 and from that moment, Tim O’Reilly [37] started to use that term in his conferences to refer to the new developments that the Web is undergoing. The precise definition of Web 2.0 is not clear. Many definitions can be found but the researchers are still discussing the definitive definition. It is not clear if the Web 2.0 is a new paradigm or simply a natural evolution of the current Web. Web 2.0 is based on the user as the main figure who is capable of creating, modifying and publishing the content of the Web pages in collaboration with other users. The user is able to interact in simplified way with the applications because they are very lightweight, and it is not required to be an expert in computer science to write your own content in applications such as blogs, wikis, social networks, etc. Many new services 2.0 are appearing everyday; Facebook, Flickr, Wikipedia and Blogspot are some clear examples of this fact. The continued development of new and innovative applications involves the appearance of new paradigms, such as in the case of Google Wave,1 a new tool which is capable of encapsulating typical functions from other Web applications such as RSS, blogs, chats, wikis, social networks, etc. The application of the capabilities of this new technology to the UDLs is one the objectives of this work in order to extend the concept of Library 2.0. The first person who used the term Library 2.0 was Casey [12] and since that moment many related works have emerged [15,48,50]. Xu [51] depicted a model (see Fig. 1) of the Library 2.0 based on three components, (i) the information, (ii) the users and (iii) the librarians. He summarizes several applications based on Web 2.0 tools (blogs, RSS, tagging, wikis, social networks, and podcasts) applied to Academic Libraries and this is the objective of this work as well, the application of the Google Wave technology to develop a recommender system that will suggest users and digital resources for collaborative purposes between the users of a University Digital Library, specially the researchers. This system allows the reduction of the necessary time to find col￾laborators and information about digital resources depending on the user needs. An example of an application of the system would be when several research groups want to request a European project. These research groups have decided to collaborate for research purposes and they request a common environment (a wave) from the university staff. They are the first members of the wave and for example the official announcement and other re￾lated documents are the first resources of the wave, but it is necessary to find new partners and old documents about the announcements from past years, etc. That is the moment in which the recommender system suggests new participants and relevant resources from the library to achieve the collaborative objectives of the wave. The proposed recommender system is mainly based on Fuzzy Logic [18,21] which has been used successfully in other pre￾vious approaches [14,23,40,41]. The rest of the paper is organized as follows. Section 2 presents the preliminaries of this work: Google Wave, Recom￾mender Systems and Fuzzy Linguistic Modeling. Section 3 presents the architecture and the main characteristics of the pro￾posed fuzzy linguistic recommender system. Section 4 presents the results of an experiment using this system and finally some conclusions and future works are pointed out. 2. Foundations 2.1. Google wave Web 2.0 proposes the use of many new applications with collaborative purposes, now the interaction between users is one of the main points of the information and communication technologies. Following this idea Google Wave has introduced a new communication and collaboration platform built around hosted conversations called waves. The wave model enables Fig. 1. Library 2.0. 1 https://wave.google.com. 1504 J. Serrano-Guerrero et al. / Information Sciences 181 (2011) 1503–1516