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 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 |
| Abstract: |
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.
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Friday, September 19, 2014 10:45 AM EDT
| Speakers: |
- 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"
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Monday, September 15, 2014 2:30 PM EDT
| 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
| 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
| 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
Wednesday, June 11, 2014 2:30 PM EDT
| 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
Wednesday, May 28, 2014 2:30 PM EDT
| 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 14, 2014 2:30 PM EDT
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. |
Wednesday, April 9, 2014 2:30 PM EDT
| Speaker: |
Dan Farrar, SAP Waterloo |
Wednesday, April 9, 2014 2:30 PM EDT
| 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. |
