Yi Yang Zhi-Cong Fang Yan Yang Hong Cai 19-20 2008 SERVICES I https://doi.org/10.1109/SERVICES-1.2008.100 https://doi.ieeecomputersociety.org/10.1109/SERVICES-1.2008.100 conf/services/2008-1 db/conf/services/services2008-1.html#YangFYC08