ubiController: Design and Implementation of Mobile Interactive User Interface Hyoseok Yoon and Woontack Woo Abstract—In ubiquitous computing, service environment is intelligent and provide users with relevant and timely service to meet demands of users. To realize this, the research for ubiquitous computing have stressed on logical processes required by the smart environment to trigger proper services at the right moment. However, little attention is paid to an actual user interface that can lead to richer interaction with the smart environment. In this paper, we analyze requirements of a user interface in ubiquitous computing environment through a prototypical implementation of user interface, ubiController. ubiController aims to support user and service interaction via a direct service control and user to user interaction with conflict notification and recommendation, all in an integrated intuitive interface on a mobile device. Index Terms— Service Discovery, Universal Control, Situation-aware I. INTRODUCTION n ubiquitous computing environment, it is essential to provide a user interface for interactions with the environment. Previous research theme for ubiquitous computing have emphasized on logical processes required to provide appropriate services, therefore populating context-aware and intelligent services in ubiquitous computing domain. However, inadequate attention is paid to an actual user interface that is utilized to interact with such intelligent environment. Numerous studies have been initiated on user interface to give more support by choosing mobile devices as the key interaction tools between users and the environment [1][2]. In this paper, we propose a mobile user interface, ubiController, to support intuitive interactions with the environment. To realize this, ubiController provides service discovery and universal control, situation-awareness and multi-user support. We identify requirements of user interface in ubiquitous computing environment by analyzing ubiController and present an outlook for mobile user interface. II. UBICONTROLLER We have developed a mobile user interface, ubiController, to be used in ubiquitous computing environment. Such an interface for user can provide both input and output for context-aware service. Here, we list three requirements for mobile user interface as follows, service discovery and universal control, situation-awareness and multi-user support. We analyze these requirements against our prototypical mobile user interface, ubiController, to see how these requirements are considered. This work was supported by both the Brain Korea 21 project and the UCN Project, the MIC 21st Century Frontier R&D Program in Korea, under CTRC at GIST. The authors are with GIST U-VR Lab., Gwangju 500-712, S. Korea (e-mail: {hyoon,wwoo}@gist.ac.kr). Fig. 1. Three Features of ubiController A. Universal Plug and Play (UPnP) and Universal Control As a first step toward interaction with the environment, a user must know what kinds of services are present and available for the user to access. When available services are notified to the user, then users can take further steps to control or interact with the services, preferably using a single device. The first step is known as service discovery, and the second step is referred as universal control. ubiController first discovers available services as a control point in the environment using UPnP [4]. Each service is connected with the UPnP service module in ubi-UCAM for compatibility. Service discovery allows and notifies users for potential functionality and universal control mechanisms allow exploration with discovered services. Service discovery requires conformity between services in the environment and the user. This conformity takes a form of standard and we utilize such a standard, Universal Plug and Play (UPnP). A service in the environment corresponds to an UPnP service and the user’s side is represented by an UPnP control point. UPnP service advertises itself to the network which can be discovered by UPnP control point. UPnP establishes basic connection between the environment and the user. However UPnP alone does not support communication based on context, so we introduce additional middleware, ubi-UCAM (Unified I 93