ER-3 Stamatia Rizou

QoS Oriented service provisioning in Cloud computing environments

Cloud computing is a disruptive technology that has changed the way that IT services are delivered and consumed. Enterprises do not rely anymore only on own computing resources, but they are able to migrate and scale out their workload on public clouds. From a user point of view, one fundamental question that arises is how a certain level of performance could be fulfilled and guaranteed, when migrating to the cloud. From a cloud provider’s perspective, this requirement leads to the problem of managing efficiently multiple services in a shared resource pool to maximize revenue, while fulfilling user needs.

Moreover, as cloud service ecosystems evolve third party individuals or businesses play an intermediate role between cloud service consumers and cloud providers to preserve customer expectations. The presence of the so-called cloud brokers lead to a more transparent control of cloud service performance and increases the competition among the cloud service providers, since cloud brokers are expertized and have a better perception of the value of cloud services. To this end, mechanisms for monitoring cloud services and discovering optimal service compositions will be of primary importance for the development of future cloud brokerage systems.

In the frame of this research project, fellow is going to investigate methods for QoS aware service provisioning in cloud environments. As it is shown in Figure 1, the performance of the cloud applications in the SaaS layer is dependent on the resource allocation in the IaaS layer. Since resource provisioning strategies define in a certain extent the QoS experienced by the end user, resource management lies within the scope of this research project. Moreover, in order to enable QoS aware service composition in complex service ecosystems, mechanisms for enhancing existing cloud brokerage systems to provide optimal service compositions will be investigated.

Main research interests:

  • Cloud resource management and performance
  • Service-oriented computing
  • Distributed Systems architecture
  • Self-adaptive systems




Rizou S., Angouras G.: ORBI: An Internet service for self-employed professionals. In 2013 IEEE Ninth World Congress on Services (SERVICES), June 27-July 2, Santa Clara Marriott, CA, USA, 2013, pp. 221-226, LINK

Rizou S., Verginadis Y., Mentzas G.: Continuous Service Optimization as Cloud Brokerage Service (Postion Paper). In 3rd International Conference on Cloud Computing and Services Science, May 8-10, Aachen, Germany, 2013. (Poster)

Rizou S., Polyviou A.: Towards value-based resource provisioning in the Cloud. In Proceedings of the 4th IEEE International Conference in Cloud Computing Technology and Science Conference, December 3-6, Taipeh, Taiwan, 2012, pp. 155-160, LINK

Kounev S., Rizou S., Zschaler S., Alexakis S., Bures T., Jezequel J., Paraskakis I., Pantelopoulos S. RELATE: A Research Training Network on Engineering and Provisioning of Service-Based Cloud Applications. In International Workshop on Hot Topics in Cloud Services (HotTopiCS 2013), April 20-21, Prague, Czech Republic, 2013, pp-51-54. (Invited Paper), LINK

Polyviou A., Pouloudi N., Rizou S.: Which Factors Affect Software-as-a-Service Selection the Most? A Study from the Customer’s and the Vendor’s Perspective. In Proceedings of the 47th Hawaii International Conference on System Sciences (HICSS 2014), January 6-9, Big Island, Hawaii, 2014. (To appear)

Hamadache K., Rizou S.: Holistic SLA Ontology for Service Evaluation. In Proceedings of 2013 International Conference on Advanced Cloud and Big Data, December 13-15, Southeast University, Nanjing, 2013, p.32-39.

Patiniotakis I., Rizou S., Verginadis Y., Mentzas G.: Managing Imprecise Criteria in Cloud Service Ranking with a Fuzzy Multi-Criteria Decision Making Method. In European Conference on Service-Oriented and Cloud Computing (ESOCC 2013), September 11-13, Malaga, Spain, 2013, pp. 34-48, LINK

This entry was posted in Research Projects, WP3. Bookmark the permalink.

Comments are closed.