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

In the last decade, significant efforts and progress have been made by both the industry and academia to meet the rapidly growing demand for wireless applications and services. To achieve more flexible, dynamic and intelligent use of the limited wireless spectrum, cooperative transmission and cognitive networking are proposed as two of the key technologies for the next generation wireless commu...

This paper presents a proposal for specifying task models for cooperative applications that allow designers to describe the relationships between the activities performed by various users involved in cooperative environments. To this end we extend the ConcurTaskTree notation so that new information useful for describing complex cooperative applications can be clearly specified. An example of ap...

Cognitive Radio (CR) networks enable dynamic spectrum access and can significantly improve spectral efficiency. Cooperative Spectrum Sensing (CSS) exploits the spatial diversity between CR users to increase sensing accuracy. However, in a realistic scenario, the trustworthy of CSS is vulnerable to Spectrum Sensing Data Falsification (SSDF) attack. In an SSDF attack, some malicious CR users deli...

A new class of systems that should appear in a next future should enable several users to lead synchronous cooperative activity by way of their computing systems. These cooperative systems should be able to operate in heterogeneous environments involved by the operating and communication environment of the user. In order to build such cooperative system it is needed to have open cooperative sys...

This paper proposes the Ring-TCM coded Amplifyand-Forward (AF) cooperative system, achieving both high spectral efficiency and optimized performance. In a cooperative communication network, individual users are encouraged not only to transmit their own data, but also relay other user’s data. This relaying transmission creates spatial diversity to combat the effect of individual severe fading an...