Jae-Hwan Jin

Supporting Collaborative Workspaces over XMPP

Collaborative workspaces provide virtual workspaces to share resources among users in a systematic manner, managing resources structurally for groups or individuals. Through collaborative workspaces, users can preserve their collaborative work as well as they effectively share their resources among group users. In this paper, we present techniques for supporting collaborative workspaces for chat groups in XMPP messaging services. In addition, based on the collaborative workspaces, we present a new shared board which supports synchronous drawing for chat groups of the messaging services with various drawing tools.

Management of User Groups and Member Authorization with Various Access Rights on the Ethereum Blockchain

Distributed applications based on the Ethereum blockchain have a great advantage in the analysis of the history of group work and the contribution factor to a group project of each group member. In these applications, multiple users share resources and their histories together in a robust way thanks to the characteristics of the blockchain that is practically impossible to be forged or modified. However, there has not yet been developed a scheme for providing a systematic management scheme of a group of users or authentication of the members of the group to allow the members to use shared resources through various access rights. In this paper, we propose a user group and authorization management scheme over the Ethereum Blockchain. In the proposed scheme, group users can use shared resources by using various access rights. To do this, we define user groups as different types according to their access rights, and present the process of authenticating user groups according to their types. The proposed scheme is designed using smart contracts, being useful in various Ethereum distributed applications requiring group workspaces.

On supporting user-defined collaborative workspaces over cloud storage

We introduce a novel cloud storage service named Uspace supporting the concept of user-defined collaborative workspace which provides the functionality of inviting unregistered people as group members and assigning appropriate access rights to them. Uspace is developed by extending the Swift storage service included in the OpenStack cloud computing system. In addition, Uspace provides a concurrency control service for coordinating resource accesses which is necessary for collaborative applications. As one of applications utilizing the Uspace service, we also present an Android application UspaceApp equipped with the features of shared whiteboards, group chats and file sharing among group members.