This book constitutes the refereed proceedings of the EUC 2006 workshops held in conjunction with the IFIP International Conference on Embedded and Ubiquitous Computing, EUC 2006, in Seoul, Korea in August 2006.

The 102 revised full papers presented were carefully reviewed and selected from 375 submissions. Topics covered by the six workshops are network-centric ubiquitous systems (NCUS 2006), security in ubiquitous computing systems (SecUbiq 2006), RFID and ubiquitous sensor networks (USN 2006), trustworthiness, reliability and services in ubiquitous and sensor networks (TRUST 2006), embedded software optimization (ESO 2006), and multimedia solution and the assurance in the ubiquitous information systems (MSA 2006).