Choonsung Shin, Daeho Han and Woontack Woo 48 Conflict Management for Media Services by exploiting Service Profile and User Preference Choonsung Shin, Daeho Han and Woontack Woo Abstract— In this paper, we propose Context Manager to resolve conflicts for Context-aware Media services in smart home environments. Conflicts arise when multiple users access a Media service or when various Media services share limited resources to provide customized responses. In order to resolve conflicts among users, the Context Manager sums up preferences of users who collide with each other and recommends specific contents ordered by the summed preference. It also resolves conflicts among Media services by selecting a Media service with the highest preference. Furthermore, Context Manager resolves conflicts among Media services occupied by users with the Media service recommendation. During experiments on ubiHome, a smart home test-bed, the proposed method resolved conflicts among users and Media services while giving higher satisfaction to users than a resolution method selecting a specific user. Therefore, we expect the proposed management method can play a vital role in Context-aware Media services for offering personalized services to users by resolving service conflicts among Media services as well as users. Index Terms—Context-awareness, Service Conflicts, Service Profile, Media Service, User Preference I. INTRODUCTION H in E aim of ubiquitous computing is to provide users with telligent services based on the information obtained from distributed and invisible computing resources [1]. Users exploit these services without any cumbersome interface or learning procedures. Therefore, context-aware applications are considered to be important applications in the ubiquitous computing environments that offer appropriate services to users by utilizing contextual information of users and their surroundings [2][3]. Especially, context-aware Media services are one of the emerging applications for smart home environments. The Home Media Space (HMS) allows users to teleconference with remote users through video streaming [4]. Context-based Media Player (cMP) offers various movie contents by utilizing user’s contextual information and preference [6]. Music Player Application provides functions for playing music by exploiting distributed resources, such as display and audio devices in Active Space [5]. Manuscript created June 17, 2005. This work was supported by Samsung Electronics Co., Ltd. in S.Korea Choonsung Shin is with Gwangju Institute of Science and Technology, Gwangju, 500-712, S.Korea (e-mail: cshin@gist.ac.kr ) Deaho Han is with Samsung Electronics Co., Ltd, Seoul, 135-284, S.Korea (e-mail: bighoya.han@samsung.com ) Woontack Woo is with Gwangju Institute of Science and Technology, Gwanju, 500-712, S.Korea (Corresponding author to provide phone: 82-62-970-2226, fax: 82-62-970-2249, email: wwoo@gist.ac.kr ) However, conflicts occur in context-aware media services when more than one user reaches the Media service simultaneously due to sharing of the space and service. Hughes pointed out that conflicts arise when residents share the appliances, such as radio, television, and etc. [7]. W.Keith classified the conflict problem among users as a challenge in ubiquitous computing home environments [8]. Besides, conflicts also arise when more then one Media service shares the limited resources within their environment. Ajay A considered this kind of conflicts as conflicting reactions in behavioral system [13]. Conflicts also arise when more than one user access different Media services. Meyer defined the ubiquitous computing environment as multi-user and multi device environments [9]. Furthermore, S.M. Easterbrook pointed out the complexity of home environments like “the less cohesive the group, the more conflicts” [11]. Consequently, in order to develop Context-aware Media services for home environments, it is necessary to resolve conflicts not only among Media services and among users, but also among Media services provided to different users. Meanwhile, most research, aimed on resolving conflicts, has been done on smart home and intelligent office. MusicFX supports group music selection in a fitness center by exploiting users’ preferences on each music station [12]. Reactive Behavioral System (ReBa) resolves conflicts among devices in office environments by applying layering architecture of activity bundles consisting of users’ activities and reactions of environments [14]. Reconfigurable Context-Sensitive Middleware for Pervasive Computing (RCSM), an object- based framework, ensures independence between sensors and application services, forms ad-hoc communication between them, and delivers the necessary context to the applications [16]. Context Toolkit collects, interprets, and delivers context between sensors and application services [15]. Contextual Information Service (CIS) manages contextual information such as location and characteristics of users, devices, and status of network to provide contexts to application services [17]. Nevertheless, context management techniques in the previous research have various limitations when they are applied to multi-user environments with various applications. MusicFX only utilizes users’ preferences on all situations of users and lacks consideration of multiple services [12]. In case of ReBa, it is difficult to provide particular services to each user because ReBa focuses on the service for grouped users by inferring main activities from the environment [14]. In the RCSM, context management does not consider shared devices T