On Friday, April 8, Thao N. Pham successfully defended her thesis. Congratulations Thao! More information can be found here.

Committee
Panos K. Chrysanthis, Professor, University of Pittsburgh
Alexandros Labrinidis, Associate Professor, University of Pittsburgh
Adam Lee, Associate Professor, University of Pittsburgh
Christos Faloutsos, Professor, Carnegie Mellon University

Abstract
Data Stream Management Systems (DSMSs) offer the most effective solution for processing data streams by efficiently executing continuous queries (CQs) over the incoming data. CQs inherently have different levels of criticality and hence different levels of expected quality of service (QoS) and quality of data (QoD). Adhering to such expected QoS/QoD metrics is even more important in cases of multi-tenant data stream management services. In this dissertation, we propose DILoS, a framework that, through priority-based scheduling and load shedding, supports differentiated QoS and QoD for multiple classes of CQs. Unlike existing works that consider scheduling and load shedding separately, DILoS is a novel unified framework that exploits the synergy between scheduling and load shedding. For the realization of DILoS, we propose ALoMa and SEamLeSS, two general, adaptive load managers. Our load managers perform better than the state-of-the-art alternatives in three dimensions: (1) they automatically tune the headroom factor, (2) they honor the delay target, and (3) they are applicable to complex query networks with shared operators.

As a preliminary step toward our future work on a large-scale resource management using DILoS, we also implemented UniMiCo, a protocol to migrate continuous queries without interupting the execution of the queries. Our experiments showed that UniMiCo produced correct outputs and did not introduce any hiccup in the response time of the queries.

Thao

Thao with (from left to right) Professor Alexandros Labrinidis (co-advisor), Professor Panos Chrythansis (advisor), Professor Christos Faloutsos (Carnegie Mellon University), Professor Adam Lee just after her defense.