One of the main challenges of centralised social networks is having a central provider that stores the data which imposes some limitations to preserve the privacy of users’ data. However, one of the decentralised architectures is peer-to-peer network that every user takes the responsibility of storing and managing his/her data. Although the privacy of data is increased in these networks, authorised friends must have access to the shared data when the user is not online in the network. For this purpose, the user selects some friends and copies his/her data in their space. On the other hand, the amount of used space and the total number of replicas must be reduced as much as possible. In this study, the authors provide some solutions to reduce the amount of used space and the total number of replicas to increase data availability. In this way, they segment the user's data and consider the stability of copy-location, i.e. the selected friends who have a copy of the user's data. The performance evaluation of the proposed methods shows that they considerably reduce the amount of used space as well as the total number of replicas in comparison to other approaches.

中文翻译：

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对等在线社交网络中的数据可用性改进

集中式社交网络的主要挑战之一是拥有一个存储数据的中央提供商，这对保留用户数据的隐私施加了一些限制。但是，分散式体系结构之一是对等网络，每个用户都有责任存储和管理他/她的数据。尽管在这些网络中增加了数据的隐私性，但是当用户不在网络中时，授权的朋友必须有权访问共享数据。为此，用户选择一些朋友并将其数据复制到他们的空间中。另一方面，必须尽可能减少已用空间的数量和副本的总数。在这项研究中，作者提供了一些解决方案，以减少已用空间的数量和副本总数，以提高数据可用性。通过这种方式，他们对用户数据进行细分，并考虑复制位置的稳定性，即选择的拥有用户数据副本的朋友。所提出方法的性能评估表明，与其他方法相比，它们大大减少了已用空间的数量以及副本的总数。