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Wednesday, November 12, 2014 — 2:30 PM EST
Speaker: Peter Bumbulis, SAP Waterloo
Abstract: I'll be talking about the following paper as well as a bit about time synchronization. There will probably be a bit about Spanner as well.
Clock-SI: Snapshot Isolation for Partitioned Data Stores Using Loosely Synchronized Clocks, SRDS 2013.
Wednesday, November 5, 2014 — 2:30 PM EST
Speaker: Arian Baer, FTW Telecom Research Centre, Vienna
Abstract: Shared workload optimization is feasible if the set of tasks to be executed is known in advance, as is the case in updating a set of materialized views or executing an extract-transform-load workflow. In this talk, we consider data-intensive shared workloads with precedence constraints arising from data dependencies, i.e., before executing some task, other tasks may have to run first and generate some data needed by the next task(s).
Wednesday, October 29, 2014 — 2:30 PM EDT
Speaker: Ani Nica, SAP Waterloo
Wednesday, October 15, 2014 — 2:30 PM EDT

Part of the Data Systems Seminar Series (2014-2015) 

Speaker: Jignesh Patel, University of Wisconsin
Wednesday, October 8, 2014 — 2:30 PM EDT
Speaker: Jeff Pound, SAP Waterloo
Abstract: This talk is inspired by the pop sensation and distributed database enthusiast Carly Rae Jepson. In this talk we will discuss her hit song "Call Me Maybe", a poetic ode to the challenges in building fault-tolerant distributed systems.
Wednesday, October 1, 2014 — 2:30 PM EDT
Speaker: Greg Drzadzewski

On-Line Analytical Processing (OLAP) systems are commonly used on top of structured data to help users make sense of large data collections by providing them with summary information that can be examined at various levels of detail. Partial materialization has been used as part of these OLAP systems as a way of reducing the time required to calculate summaries as well as satisfying the constraints of limited storage and available time for updates.

Wednesday, September 24, 2014 — 2:30 PM EDT

Part of the Data Systems Seminar Series (2014-2015)

Speaker: Frank Dehne, Carleton University
Friday, September 19, 2014 — 10:45 AM EDT
  • David Cheriton, Stanford University, 10:45am
    "HICAMP Bitmap: Space-efficient updatable bitmap index for in-memory databases"
  • Ihab Ilyas, University of Waterloo, 3:00pm
    "Data Cleaning from Theory to Practice"
  • M. Tamer Özsu, University of Waterloo, 3:45pm "Web Data Management in the RDF Age"
Monday, September 15, 2014 — 2:30 PM EDT
Speaker: Taras Kinash
Abstract: Answering object queries (i.e. instance retrieval) is a central task in ontology based data access (OBDA). Performing this task involves reasoning with respect to a knowledge base K (i.e. ontology) over some description logic (DL) dialect L. As the expressive power of L grows, so does the complexity of reasoning with respect to K. Therefore, eliminating the need to reason with respect to a knowledge base K is desirable.
Wednesday, August 6, 2014 — 2:30 PM EDT
Abstract: Minyang Han, K. Daudjee, K. Ammar, M. T. Özsu, X. Wang, T. Jin, An Experimental Comparison of Pregel-like Graph Processing Systems.

Güneş Aluç, M. T. Özsu, K. Daudjee, Workload Matters: Why RDF Databases Need a New Design.
Tuesday, August 5, 2014 — 3:00 PM EDT
Speaker: Alistair Moffat, , Department of Computing and Information Systems, The University of Melbourne
Abstract: Web search services process thousands of queries per second, and filter their answers from collections containing very large amounts of data. Fast response to queries is a critical service expectation. The well-known WAND (Weak AND) processing strategy is one way of reducing the amount of computation necessary when executing such a query.
Wednesday, July 23, 2014 — 2:30 PM EDT
Speaker: Jaemyung Kim
Abstract: Hot standby techniques are widely used to implement highly available database systems. These techniques make use of two copies of the database, an active copy and a backup that is managed by the standby. Synchronization of these two database copies is the responsibility of the database systems than manage them. However, database systems are often deployed in settings in which a reliable, persistent, network-accessible storage service (such as cloud block storage services, cluster file systems, or NAS) is available.
Wednesday, July 16, 2014 — 2:30 PM EDT
Speaker: Zhiping Wu
Abstract: While many access control models have been proposed, little work has been done on the efficiency of access control systems. Because the access control sub-system of an Enterprise Content Management (ECM) system may be a bottleneck, we investigate the representation of permissions to improve its efficiency.
Wednesday, July 9, 2014 — 2:30 PM EDT
Speaker: Mohamed Sabri
Wednesday, June 18, 2014 — 2:30 PM EDT

Part of the Data Systems Seminar Series (2013-2014)

Speaker: Radu Sion, Stony Brook University
Wednesday, June 11, 2014 — 2:30 PM EDT
Speaker: Michael Mior
Abstract: Selecting appropriate indices and materialized views is critical for high performance in relational databases. By example, we show that the problem of schema optimization is also highly relevant for NoSQL databases.
Wednesday, June 4, 2014 — 2:30 PM EDT
Speaker: Frank Tompa
Wednesday, May 28, 2014 — 2:30 PM EDT
Speaker: Olaf Hartig
Abstract: Traversal-based query execution is a recent approach to query the Web as if it was a distributed database. The novelty of this approach lies in integrating a traversal-based retrieval of Web data into the query execution process. Hence, this approach does not assume a-priori a fixed set of potentially relevant data sources; instead, the traversal process discovers data and data sources on the fly.
Wednesday, May 21, 2014 — 2:30 PM EDT

Part of the Data Systems Seminar Series (2013-2014)

Speaker: Alexandros Labrinidis, University of Pittsburgh
Wednesday, May 14, 2014 — 2:30 PM EDT
Speaker: Daniel Nicoara
Wednesday, May 7, 2014 — 2:30 PM EDT
Speaker: Matteo Riondato, Brown University
Abstract: Frequent Itemsets mining is one of the key tasks in knowledge discovery from databases. The cost of mining algorithms for this problem depends on the number of itemsets and on the size of the dataset.
Tuesday, May 6, 2014 — 11:00 AM EDT

Part of the Data Systems Seminar Series (2013-2014) 

Speaker: Timothy Roscoe, ETH Zürich
Wednesday, April 9, 2014 — 2:30 PM EDT
Speaker: Dan Farrar, SAP Waterloo
Wednesday, April 9, 2014 — 2:30 PM EDT
Speaker: Chang Ge
Abstract: The bitemporal data model associates two time intervals with each record - system time and application time - denoting the validity of the record from the perspective of the database and of the real wold, respectively. One issue that has not yet been addressed is how to efficiently answer sliding window queries in this model.


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