Under the environment of Service-Oriented Architecture (SOA), service users have to decide how to choose the proper provider from the candidates to obtain optimal service level. The existing approaches based on the optimization theories usually ignore the decision conflicts among users, which result in periodic QoS fluctuation and poor system performance. This paper treated the service selectio...

We propose a new display table that allows multiple users to interact with both private and public information on a shared display in a face-to-face co-located setting. With this table users can create, manage and share information intuitively, strategically and cooperatively by naturally moving around the display. Users can interactively control private and public information space seamlessly ...

We address appropriate user modeling in order to generate cooperative responses to each user in spoken dialogue systems. Unlike previous studies that focus on user’s knowledge or typical kinds of users, the user model we propose is more comprehensive. Specifically, we set up three dimensions of user models: skill level to the system, knowledge level on the target domain and the degree of hastin...

The complexity and the extension of tasks in the world today demand an extensive interaction among people with different knowledge backgrounds, who need to work in cooperation, aiming at a common goal. In this paper, we present a method to model the tasks and actions that a group of users carries out when working cooperatively through a computational system integace. For this purpose, we use sc...

Cooperative work on shared information requires different kind of computing system support to coordinate the work of multiple users, to establish mutual awareness and to ensure consistency. These issues are currently tackled separately in various loosely related areas, like workflow systems, groupware, and advanced transactional models. We present a transactional model that provides a core func...

Spectrum sensing is the key element in cognitive radio networks for detecting the primary users. Due to the destructive conditions of sensing channel such as multipath fading and shadowing, local sensing is not fitting the requirements for reliable detection. Therefore, cooperative spectrum sensing is introduced to detect the primary user more accurately. Clustering approach is considered as an...

Title of Dissertation: DYNAMIC SPECTRUM ALLOCATION AND SHARING IN COGNITIVE COOPERATIVE NETWORKS Beibei Wang, Doctor of Philosophy, 2009 Dissertation directed by: Professor K. J. Ray Liu Department of Electrical and Computer Engineering The dramatic increase of service quality and channel capacity in wireless networks is severely limited by the scarcity of energy and bandwidth, which are the tw...

To enable mobile stations (MSs) of secondary users (SUs) in cognitive radio (CR) networks sharing a common channel with MSs of primary users (PUs) is an important but challenging issue. In this paper, a cooperative spatial multiplexing (CSM) scheme is proposed, where base station (BS) in CR network has K antennas and each SU or PU has one antenna only, and BS supports PUs and SUs by K spatial c...

This paper presents an active, cooperative transaction model for shared databases which supports the collaboration of users and user groups in product design. The described cooperative transaction model is a component of an active database system that potentially represents all information needed during the product development process. The rules of this active database system are used for autom...