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Peer to Peer (P2P) technologies have been among most disruptive technologies after Internet. Indeed, the emergence of the P2P technologies changed drastically the concepts, paradigms and protocols of sharing and communication in large scale distributed systems. Since early 2000 years (Oram, 2001; Sula, et al., 2014; Di Stefano, Morana, & Zito, 2011; Sawamura, Barolli, Aikebaier, Takizawa, & Enokido, 2011; Higashino, Hayakawa, Takahashi, Kawamura, & Sugahara, 2014; Nakamura, Enokido, & Takizawa, 2019), the nature of the sharing and the direct communication among peers in the system, being these machines or people, makes possible to overcome the limitations of the flat communications through email, newsgroups and other forum-based communication forms (Jayanthi, Kumar, & Swathi, 2018). Various consistency maintenance strategies of content sharing in pure P2P networks have been investigated. Meanwhile, the increasing size of resources and users in large-scale distributed systems has led to a scalability problem. The self-organizing, fault tolerance and decentralized nature of P2P technology, which helps to reduce the management cost of grid infrastructure, is good for solving problems (Gueye, Flauzac, Rabat, & Niang, 2017). However, the ones applied in hybrid P2P networks have not been investigated enough. In hybrid P2P networks, when an update of a content item happens on a peer, it is necessary to propagate the update to all the peers which have obsolete replicas of the same content item (Yoichi & Sugawara, 2017).
The usefulness of P2P technologies has been shown for the development of standalone applications. Also, P2P technologies, paradigms and protocols have penetrated other large-scale distributed systems such as Mobile Ad hoc Networks (MANETs), groupware systems, mobile systems to achieve efficient sharing, communication, coordination, replication, awareness and synchronization. In fact, for every new form of Internet-based distributed systems, we are seeing how P2P concepts and paradigms play an important role to enhance the efficiency and effectiveness of such systems or to enhance information sharing and online collaborative activities of groups of people. Mobile computing has many application domains. One important domain is that of mobile applications supporting collaborative work. In a collaborative work, the members of the team have to take decision or solve conflicts in project development and therefore members have to vote (Liu, Ozera, Matsuo, & Barolli, 2017).
Awareness is a key feature of groupware systems. In its simplest terms, awareness can be defined as the system’s ability to notify the members of a group for changes occurring in the group’s workspace. Awareness systems for online collaborative work have been proposed since in early stages of Web technology. Such proposals started by approaching workspace awareness, aiming to inform users about changes occurring in the shared workspace. In P2P groupware systems, group processes may be more efficient because peers can be aware of the status of other peers in the group and can interact directly and share resources with peers in order to provide additional scaffolding or social support. Moreover, P2P systems are pervasive and ubiquitous in nature, thus enabling contextualized awareness.
Fuzzy Logic (FL) is the logic underlying modes of reasoning which are approximate rather than exact. The importance of FL derives from the fact that most modes of human reasoning and especially common-sense reasoning are approximate in nature. FL uses linguistic variables to describe the control parameters. By using relatively simple linguistic expressions it is possible to describe and grasp very complex problems (Bylykbashi, Qafzezi, Ikeda, Matsuo, & Barolli, 2020). A very important property of the linguistic variables is the capability of describing imprecise parameters.
The concept of a fuzzy set deals with the representation of classes whose boundaries are not determined. It uses a characteristic function, taking values usually in the interval [0, 1]. The fuzzy sets are used for representing linguistic labels. This can be viewed as expressing an uncertainty about the clear-cut meaning of the label. But important point is that the valuation set is supposed to be common to the various linguistic labels that are involved in the given problem (Qafzezi, Bylykbashi, Spaho, & Barolli, 2019).