Database Systems (TODS)


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ACM Transactions on Database Systems (TODS) - Invited Paper from EDBT 2015, Invited Paper from PODS 2015 and Regular Papers, Volume 41 Issue 4, December 2016

Section: Invited Paper from EDBT 2015

Building a Hybrid Warehouse: Efficient Joins between Data Stored in HDFS and Enterprise Warehouse
Yuanyuan Tian, Fatma Özcan, Tao Zou, Romulo Goncalves, Hamid Pirahesh
Article No.: 21
DOI: 10.1145/2972950

The Hadoop Distributed File System (HDFS) has become an important data repository in the enterprise as the center for all business analytics, from SQL queries and machine learning to reporting. At the same time, enterprise data warehouses (EDWs)...

Section: Invited Paper from EDBT 2015

Joins via Geometric Resolutions: Worst Case and Beyond
Mahmoud Abo Khamis, Hung Q. Ngo, Christopher Ré, Atri Rudra
Article No.: 22
DOI: 10.1145/2967101

We present a simple geometric framework for the relational join. Using this framework, we design an algorithm that achieves the fractional hypertree-width bound, which generalizes classical and recent worst-case algorithmic results on computing...

Section: Invited Paper from EDBT 2015

The Goal Behind the Action: Toward Goal-Aware Systems and Applications
Dimitra Papadimitriou, Georgia Koutrika, John Mylopoulos, Yannis Velegrakis
Article No.: 23
DOI: 10.1145/2934666

Human activity is almost always intentional, be it in a physical context or as part of an interaction with a computer system. By understanding why user-generated events are happening and what purposes they serve, a system can offer a significantly...

Exploiting Integrity Constraints for Cleaning Trajectories of RFID-Monitored Objects
Bettina Fazzinga, Sergio Flesca, Filippo Furfaro, Francesco Parisi
Article No.: 24
DOI: 10.1145/2939368

A probabilistic framework for cleaning the data collected by Radio-Frequency IDentification (RFID) tracking systems is introduced. What has to be cleaned is the set of trajectories that are the possible interpretations of the readings: a...

Skycube Materialization Using the Topmost Skyline or Functional Dependencies
Sofian Maabout, Carlos Ordonez, Patrick Kamnang Wanko, Nicolas Hanusse
Article No.: 25
DOI: 10.1145/2955092

Given a table T(Id, D1, …, Dd), the skycube of T is the set of skylines with respect to to all nonempty subsets (subspaces) of the set of all dimensions {D1,...

Extending the Kernel of a Relational DBMS with Comprehensive Support for Sequenced Temporal Queries
Anton Dignös, Michael H. Böhlen, Johann Gamper, Christian S. Jensen
Article No.: 26
DOI: 10.1145/2967608

Many databases contain temporal, or time-referenced, data and use intervals to capture the temporal aspect. While SQL-based database management systems (DBMSs) are capable of supporting the management of interval data, the support they offer can...

Guarded-Based Disjunctive Tuple-Generating Dependencies
Pierre Bourhis, Marco Manna, Michael Morak, Andreas Pieris
Article No.: 27
DOI: 10.1145/2976736

We perform an in-depth complexity analysis of query answering under guarded-based classes of disjunctive tuple-generating dependencies (DTGDs), focusing on (unions of) conjunctive queries ((U)CQs). We show that the problem under investigation is...