We cordially welcome you to the proceedings of the 2006 International Symposium on Ubiquitous Computing Systems (UCS) held in Seoul, Korea. UCS has been a symposium for dissemination of state-of-the-art research and engineering practices in ubiquitous computing with particular emphasis on systems and software. 2006 UCS was the third of this series of international symposia, and its importance is increasing as information technology industries are recognizing ubiquitous systems to be one of their top priorities. This year the symposium was organized by u-Korea Forum, Su- kyunkwan University, The Electronic Times, and UCN, Korea. It was also sponsored by the Korea Ministry of Information and Communication, KISS, KIPS, KICS, NCA from Korea and IPSJ SIGUBI, IEICE URON, and UNF from Japan. This year we attracted 359 high-quality paper submissions from all over the world. Among them, 41 papers representing 11 countries were selected to be included in the technical program. This very low acceptance rate of about 11% clearly demonstrates the high quality of the conference, and this tradition will continue in the upcoming years. Three distinguished speakers were also invited for keynote speeches, who enlightened the audience on ubiquitous computing theory and application.

We cordially welcome you to the proceedings of the 2006 International Symposium on Ubiquitous Computing Systems (UCS) held in Seoul, Korea. UCS has been a symposium for dissemination of state-of-the-art research and engineering practices in ubiquitous computing with particular emphasis on systems and software. 2006 UCS was the third of this series of international symposia, and its importance is increasing as information technology industries are recognizing ubiquitous systems to be one of their top priorities. This year the symposium was organized by u-Korea Forum, Su- kyunkwan University, The Electronic Times, and UCN, Korea. It was also sponsored by the Korea Ministry of Information and Communication, KISS, KIPS, KICS, NCA from Korea and IPSJ SIGUBI, IEICE URON, and UNF from Japan. This year we attracted 359 high-quality paper submissions from all over the world. Among them, 41 papers representing 11 countries were selected to be included in the technical program. This very low acceptance rate of about 11% clearly demonstrates the high quality of the conference, and this tradition will continue in the upcoming years. Three distinguished speakers were also invited for keynote speeches, who enlightened the audience on ubiquitous computing theory and application.

We cordially welcome you to the proceedings of the 2007 International S- posium on Ubiquitous Computing Systems (UCS) held at Akihabara, Tokyo, Japan. UCS has become a symposium for the dissemination of state-of-the-art research and engineering practices in ubiquitous computing with particular - phasis on systems and software. UCS 2007 was the fourth of this series of int- nationalsymposia.ThiswastheyearfortheNextGenerationNetwork(NGN)to be commercially launched so that the Internet could become the infrastructure forcommunicationsandcomputingsubstitutingtheNGNintelephonenetworks. The maturity of the Internet encourages the research and development of the nextcomputing systems,where ubiquitous computing is recognizedasone ofthe most promising computing paradigms. This symposium was organized by IPSJ SIGUBI, IEICE USN and UCN, Korea, in cooperation with the IEEE Tokyo Section, IPSJ SIGEMB, IEICE Smart Info-media Systems Technical Group, and Human Interface Society. It was also sponsored by Ubiquitous Networking Forum, Nokia, NTT, SCAT, IISF and TAF. Thisyear,wehad96submissionsfrom18countries.TheProgramCommittee reviewed all the papers carefully and then selected 16 full papers and 8 short papers. The very low acceptance rate of about 22.6% clearly demonstrates the high quality of the conference, and this tradition will continue in the upcoming conferences. Two distinguished speakers were also invited for keynote speeches, who enlightened the audience on ubiquitous computing and applications. The high-quality technical program of UCS 2007 depends very much on the precise and stringent review process. The Technical Program Committee c- sistedof62excellentmembers.Mostreviewswarealmostofjournalpaperreview quality, and the paper selection was very serious and strict. Along with the symposium, we also o?ered a workshop and a poster session.

We cordially welcome you to the proceedings of the 2006 International Symposium on Ubiquitous Computing Systems (UCS) held in Seoul, Korea. UCS has been a symposium for dissemination of state-of-the-art research and engineering practices in ubiquitous computing with particular emphasis on systems and software. 2006 UCS was the third of this series of international symposia, and its importance is increasing as information technology industries are recognizing ubiquitous systems to be one of their top priorities. This year the symposium was organized by u-Korea Forum, Su- kyunkwan University, The Electronic Times, and UCN, Korea. It was also sponsored by the Korea Ministry of Information and Communication, KISS, KIPS, KICS, NCA from Korea and IPSJ SIGUBI, IEICE URON, and UNF from Japan. This year we attracted 359 high-quality paper submissions from all over the world. Among them, 41 papers representing 11 countries were selected to be included in the technical program. This very low acceptance rate of about 11% clearly demonstrates the high quality of the conference, and this tradition will continue in the upcoming years. Three distinguished speakers were also invited for keynote speeches, who enlightened the audience on ubiquitous computing theory and application.

We cordially welcome you to the proceedings of the 2006 International Symposium on Ubiquitous Computing Systems (UCS) held in Seoul, Korea. UCS has been a symposium for dissemination of state-of-the-art research and engineering practices in ubiquitous computing with particular emphasis on systems and software. 2006 UCS was the third of this series of international symposia, and its importance is increasing as information technology industries are recognizing ubiquitous systems to be one of their top priorities. This year the symposium was organized by u-Korea Forum, Su- kyunkwan University, The Electronic Times, and UCN, Korea. It was also sponsored by the Korea Ministry of Information and Communication, KISS, KIPS, KICS, NCA from Korea and IPSJ SIGUBI, IEICE URON, and UNF from Japan. This year we attracted 359 high-quality paper submissions from all over the world. Among them, 41 papers representing 11 countries were selected to be included in the technical program. This very low acceptance rate of about 11% clearly demonstrates the high quality of the conference, and this tradition will continue in the upcoming years. Three distinguished speakers were also invited for keynote speeches, who enlightened the audience on ubiquitous computing theory and application.

We cordially welcome you to the proceedings of the 2007 International S- posium on Ubiquitous Computing Systems (UCS) held at Akihabara, Tokyo, Japan. UCS has become a symposium for the dissemination of state-of-the-art research and engineering practices in ubiquitous computing with particular - phasis on systems and software. UCS 2007 was the fourth of this series of int- nationalsymposia.ThiswastheyearfortheNextGenerationNetwork(NGN)to be commercially launched so that the Internet could become the infrastructure forcommunicationsandcomputingsubstitutingtheNGNintelephonenetworks. The maturity of the Internet encourages the research and development of the nextcomputing systems,where ubiquitous computing is recognizedasone ofthe most promising computing paradigms. This symposium was organized by IPSJ SIGUBI, IEICE USN and UCN, Korea, in cooperation with the IEEE Tokyo Section, IPSJ SIGEMB, IEICE Smart Info-media Systems Technical Group, and Human Interface Society. It was also sponsored by Ubiquitous Networking Forum, Nokia, NTT, SCAT, IISF and TAF. Thisyear,wehad96submissionsfrom18countries.TheProgramCommittee reviewed all the papers carefully and then selected 16 full papers and 8 short papers. The very low acceptance rate of about 22.6% clearly demonstrates the high quality of the conference, and this tradition will continue in the upcoming conferences. Two distinguished speakers were also invited for keynote speeches, who enlightened the audience on ubiquitous computing and applications. The high-quality technical program of UCS 2007 depends very much on the precise and stringent review process. The Technical Program Committee c- sistedof62excellentmembers.Mostreviewswarealmostofjournalpaperreview quality, and the paper selection was very serious and strict. Along with the symposium, we also o?ered a workshop and a poster session.