  Cloud Computing is a business model revolution more than a technological one.
It capitalized on various technologies that have proved themselves and reshaped
the use of computers by replacing their local use by a centralized one where
shared resources are stored and managed by a third-party in a way transparent
to end-users. With this new use came new needs and one of them is the need to
search through Cloud services and select the ones that meet certain
requirements. To address this need, we have developed, in a previous work, the
Cloud Service Research and Selection System (CSRSS) which aims to allow Cloud
users to search through Cloud services in the database and find the ones that
match their requirements. It is based on the Skyline and ELECTRE IS. In this
paper, we improve the system by introducing 7 new dimensions related to QoS
constraints. Our work's main contribution is conceiving an Agent that uses both
the Skyline and an outranking method, called ELECTREIsSkyline, to determine
which Cloud services meet better the users' requirements while respecting QoS
properties. We programmed and tested this method for a total of 10 dimensions
and for 50 000 cloud services. The first results are very promising and show
the effectiveness of our approach.
