Walid G. Aref

Publications (108)2.71 Total impact

• Article: Spatial Queries with Two kNN Predicates

  Ahmed M. Aly, Walid G. Aref, Mourad Ouzzani
  [show abstract] [hide abstract]
  ABSTRACT: The widespread use of location-aware devices has led to countless location-based services in which a user query can be arbitrarily complex, i.e., one that embeds multiple spatial selection and join predicates. Amongst these predicates, the k-Nearest-Neighbor (kNN) predicate stands as one of the most important and widely used predicates. Unlike related research, this paper goes beyond the optimization of queries with single kNN predicates, and shows how queries with two kNN predicates can be optimized. In particular, the paper addresses the optimization of queries with: (i) two kNN-select predicates, (ii) two kNN-join predicates, and (iii) one kNN-join predicate and one kNN-select predicate. For each type of queries, conceptually correct query evaluation plans (QEPs) and new algorithms that optimize the query execution time are presented. Experimental results demonstrate that the proposed algorithms outperform the conceptually correct QEPs by orders of magnitude.
  07/2012;
• Article: Irregularity in high-dimensional space-filling curves.

  Mohamed F. Mokbel, Walid G. Aref
  Distributed and Parallel Databases. 01/2011; 29:217-238.
• Conference Proceeding: A database server for next-generation scientific data management.

  Mohamed Y. Eltabakh, Walid G. Aref, Ahmed K. Elmagarmid
  Workshops Proceedings of the 26th International Conference on Data Engineering, ICDE 2010, March 1-6, 2010, Long Beach, California, USA; 01/2010
• Source

  Available from: psu.edu

  Article: Casper*: Query processing for location services without compromising privacy.

  Chi-Yin Chow, Mohamed F. Mokbel, Walid G. Aref
  ACM Trans. Database Syst. 01/2009; 34.
• Conference Proceeding: Location-aware privacy and more: a systems approach using context-aware database management systems.

  Walid G. Aref, Hicham G. Elmongui, Mourad Ouzzani
  Proceedings of the 2nd SIGSPATIAL ACM GIS 2009 International Workshop on Security and Privacy in GIS and LBS, SPRINGL 2009, November 3, 2009, Seattle, WA, USA; 01/2009
• Conference Proceeding: Managing Biological Data using BDBMS.

  Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref, Ahmed K. Elmagarmid, Yasin Laura-Silva, Muhammad U. Arshad, David E. Salt, Ivan Baxter
  Proceedings of the 24th International Conference on Data Engineering, ICDE 2008, April 7-12, 2008, Cancún, México; 01/2008
• Source

  Available from: Rahul Shah

  Conference Proceeding: The SBC-tree: an index for run-length compressed sequences.

  Mohamed Y. Eltabakh, Wing-Kai Hon, Rahul Shah, Walid G. Aref, Jeffrey Scott Vitter
  EDBT 2008, 11th International Conference on Extending Database Technology, Nantes, France, March 25-29, 2008, Proceedings; 01/2008
• Source

  Available from: Mohamed Y. Eltabakh

  Article: bdbms -- A Database Management System for Biological Data

  Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref
  [show abstract] [hide abstract]
  ABSTRACT: Biologists are increasingly using databases for storing and managing their data. Biological databases typically consist of a mixture of raw data, metadata, sequences, annotations, and related data obtained from various sources. Current database technology lacks several functionalities that are needed by biological databases. In this paper, we introduce bdbms, an extensible prototype database management system for supporting biological data. bdbms extends the functionalities of current DBMSs to include: (1) Annotation and provenance management including storage, indexing, manipulation, and querying of annotation and provenance as first class objects in bdbms, (2) Local dependency tracking to track the dependencies and derivations among data items, (3) Update authorization to support data curation via content-based authorization, in contrast to identity-based authorization, and (4) New access methods and their supporting operators that support pattern matching on various types of compressed biological data types. This paper presents the design of bdbms along with the techniques proposed to support these functionalities including an extension to SQL. We also outline some open issues in building bdbms.
  01/2007;
• Conference Proceeding: Location-Aware Query Processing and Optimization.

  Mohamed F. Mokbel, Walid G. Aref
  8th International Conference on Mobile Data Management (MDM 2007), Mannheim, Germany, May 7-11, 2007; 01/2007
• Conference Proceeding: Place: A Distributed Spatio-Temporal Data Stream Management System for Moving Objects.

  Xiaopeng Xiong, Hicham G. Elmongui, Xiaoyong Chai, Walid G. Aref
  8th International Conference on Mobile Data Management (MDM 2007), Mannheim, Germany, May 7-11, 2007; 01/2007
• Conference Proceeding: Duplicate Elimination in Space-partitioning Tree Indexes.

  Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref
  19th International Conference on Scientific and Statistical Database Management, SSDBM 2007, 9-11 July 2007, Banff, Canada, Proceedings; 01/2007
• Conference Proceeding: Phenomenon-Aware Stream Query Processing.

  M. H. Ali, Mohamed F. Mokbel, Walid G. Aref
  8th International Conference on Mobile Data Management (MDM 2007), Mannheim, Germany, May 7-11, 2007; 01/2007
• Article: Incremental Evaluation of Sliding-Window Queries over Data Streams.

  Thanaa M. Ghanem, Moustafa A. Hammad, Mohamed F. Mokbel, Walid G. Aref, Ahmed K. Elmagarmid
  IEEE Trans. Knowl. Data Eng. 01/2007; 19:57-72.
• Source

  Available from: psu.edu

  Article: Efficient query execution on broadcasted index tree structures.

  Susanne E. Hambrusch, Chuan-Ming Liu, Walid G. Aref, Sunil Prabhakar
  Data Knowl. Eng. 01/2007; 60:511-529.
• Source

  Available from: umn.edu

  Conference Proceeding: The New Casper: A Privacy-Aware Location-Based Database Server.

  Mohamed F. Mokbel, Chi-Yin Chow, Walid G. Aref
  Proceedings of the 23rd International Conference on Data Engineering, ICDE 2007, The Marmara Hotel, Istanbul, Turkey, April 15-20, 2007; 01/2007
• Source

  Available from: psu.edu

  Article: Exploiting predicate-window semantics over data streams.

  Thanaa M. Ghanem, Walid G. Aref, Ahmed K. Elmagarmid
  SIGMOD Record. 01/2006; 35:3-8.
• Source

  Available from: Rahul Shah

  Article: Adaptive rank-aware query optimization in relational databases.

  Ihab F. Ilyas, Walid G. Aref, Ahmed K. Elmagarmid, Hicham G. Elmongui, Rahul Shah, Jeffrey Scott Vitter
  ACM Trans. Database Syst. 01/2006; 31:1257-1304.
• Source

  Available from: citeseerx.ist.psu.edu

  Conference Proceeding: The New Casper: Query Processing for Location Services without Compromising Privacy.

  Mohamed F. Mokbel, Chi-Yin Chow, Walid G. Aref
  Proceedings of the 32nd International Conference on Very Large Data Bases, Seoul, Korea, September 12-15, 2006; 01/2006
• Conference Proceeding: LUGrid: Update-tolerant Grid-based Indexing for Moving Objects.

  Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref
  7th International Conference on Mobile Data Management (MDM 2006), Nara, Japan, May 9-13, 2006; 01/2006
• Conference Proceeding: Space-Partitioning Trees in PostgreSQL: Realization and Performance.

  Mohamed Y. Eltabakh, Ramy Eltarras, Walid G. Aref
  Proceedings of the 22nd International Conference on Data Engineering, ICDE 2006, 3-8 April 2006, Atlanta, GA, USA; 01/2006