Abstract-Collaborative Information Retrieval (CIR) is the process by which people working together can collaboratively search for, share and navigate through information. Computer support for CIR currently makes use of single-user systems. CIR systems could benefit from the use of multi-user interaction to enable more than one person to collaborate using the same data sources, at the same time and in the same place. Multi- touch interaction has provided the ability for multiple users to interact simultaneously with a multi-touch surface. This paper presents a generalised architecture for multi-touch CIR applications. There are three main goals of the proposed architecture: to create hardware independence, to separate the gesture recognition and CIR information objects from the application code and to make use of an extensible gesture definition set to allow for application-specific operations. A prototype CIR tool based on this architecture is described which will be used to investigate the potential for multi-touch interaction techniques to effectively support CIR. Index Terms—Computer Supported Cooperative Work, Collaborative Information Retrieval, Human- Computer Interaction, Multi-touch, Touch Screens. I. INTRODUCTION Collaborative Information Retrieval (CIR) involves searching for, retrieving and viewing data as a group of people, using documents as data sources [1]. This activity can be supported by computer systems and can thus form a branch of Computer Supported Cooperative Work (CSCW). Collaboration may occur simultaneously, with users working together, or users may work on individual machines, distributed using networks. Personal computers do not effectively support simultaneous collaboration as they are designed for single-user, single-input environments [2]. Multi-touch surface computing has recently seen a reduction in costs and increased frequency of use [3]. This, together with its inherently multi-user nature, suggests that multi-touch interaction could be a possible solution for effectively supporting simultaneous, co-located CIR. Developers of CIR applications need to consider the application architecture to support multi-touch interaction. Currently, multi-touch application developers predominantly make use of Software Development Kits (SDKs) that are provided by the hardware manufacturers [4]. This has the major drawback that applications written using a SDK will only work on that specific hardware platform. Furthermore, the complexity of the gesture recognition algorithms needs to be separated from the application logic using a gesture recognition framework. A framework for gesture recognition can also be re-used for other CIR applications. The aim of this paper is to investigate the requirements for a multi-touch CIR framework and to propose a suitable architecture that supports these requirements. Section II reviews related work in the fields of CIR and multi-touch interaction. The requirements of a framework to support CIR using multi-touch interaction techniques are investigated in Section III. Section IV presents the proposed architecture and Section V describes a prototype design that implements this architecture. The paper concludes with key findings in Section VI and future work in this area. II. RELATED WORK This review of related work discusses literature in two main areas: Collaborative Information Retrieval, discussed in Section II-A, and Multi-touch Interaction, discussed in Section II-B. A. Collaborative Information Retrieval CIR may be defined as an information access activity that involves people interacting with other people in an information seeking and retrieval process. This may be directly between collaborators and with collaborators using documents as information sources [5]. Information sharing practices within a working environment can be broadly categorised into four types, namely strategic, paradigmatic, directive and social sharing. Directive sharing is practiced between colleagues in similar roles who share information in order to accomplish a task. Directive sharing is especially suited to computer support as it involves goal-oriented, two- way sharing [6]. CIR tasks can be divided into two categories: information seeking and information navigation. Information seeking can be defined as the process whereby information is found using querying and filtering tasks [7]. Studies have shown that collaboration is common in information seeking tasks. There are three main reasons for people to collaborate: working requirements, division of labour and diversity of skills [8]. Collaboration can improve the efficiency of achieving shared goals by delegating tasks and avoiding repetition, especially in the case of shared goals [1]. Paper documents are often the most intuitive way of sharing and annotating data. Working collaboratively at a traditional PC workstation does not provide intuitive collaborative interaction. This includes orientating the document to face another user, passing papers across a table, An Architecture to Support Multi-Touch Collaborative Information Retrieval Ivan Sams, Janet Wesson and Dieter Vogts Department of Computing Sciences Nelson Mandela Metropolitan University, P. O. Box 77000, Port Elizabeth 6031 Tel: +27 41 503 2247, Fax: +27 41 503 2831 email: Ivan.Sams@nmmu.ac.za, Janet.Wesson@nmmu.ac.za, Dieter.Vogts@nmmu.ac.za