The SBC-Tree: An Index for Run-Length Compressed Sequences (2009)
Mohamed Y. Eltabakh, Wing-kai Hon, Rahul Shah, Walid G. Aref, Jeffrey S. Vitter
Run-Length-Encoding (RLE) is a data compression technique that is used in various applications, e.g., time series, biological sequences, and multimedia databases. One of the main challenges is how to...
W.G.: The New Casper: A Privacy-Aware Location-based Databse Server (Demonstration (2009)
Mohamed F. Mokbel, Chi-yin Chow, Walid G. Aref
This demo presents Casper; a framework in which users entertain anonymous location-based services. Casper consists of two main components; the location anonymizer that blurs the users ’ exact...
F.: 2004, ‘Continuous Query Processing in Spatio-temporal Databases (2009)
Mohamed F. Mokbel, Xiaopeng Xiong, Moustafa A. Hammad, Walid G. Aref
Abstract. The tremendous increase in the use of cellular phones, GPS-like devices, and RFIDs results in highly dynamic environments where objects as well as queries are continuously moving. In this...
Managing Biological Data using bdbms (2009)
Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref, Ahmed K. Elmagarmid, Yasin Laura-silva, Muhammad U. Arshad, ...
1 Abstract — We demonstrate bdbms, an extensible database engine for biological databases. bdbms started on the observation that database technology has not kept pace with the specific requirements...
SNJoin – A Scalable Join in Sensor-Network PhenomenaBases (2008)
Mohamed H. Ali, Mourad Ouzzani, Walid G. Aref, Ibrahim Kamel
A phenomenon appears in a sensor network when a group of sensors continuously generate a simi-lar behavior over a period of time. PhenomenaBases (or databases of phenomena) are equipped with...
The Indiana Center for Database Systems at Purdue University (2008)
Mourad Ouzzani, Walid G. Aref, Elisa Bertino, Ann Christine Catlin, Christopher W. Clifton, Wing-kai Hon, ...
The Indiana Center for Database Systems (ICDS) at Purdue University has embarked in an ambitious endeavor to become a premiere world-class database research center. This goal is substantiated by the...
Mohamed F. Mokbel, Walid G. Aref, Hu Cao, Ouri Wolfson, Bo Xu, Huabei Yin, ...
The Bulletin of the Technical Committee on Data Engineering is published quarterly and is distributed to all TC members. Its scope includes the design, implementation, modelling, theory and...
Thanaa M. Ghanem, Thanaa M. Ghanem, Moustafa A. Hammad, Mohamed F. Mokbel, Walid G. Aref, Ahmed K
Seeking a position in Computer Science to utilize my experience in the following areas: systemsoriented research and implementation, databases, data stream management systems, continuous query...
Amdb A Design, Tool Access, Methods Marcel Kornacker, Mehul Shah, Joseph M. Hellerstein, Michael Cammert, ...
is published quarterly and is distributed to all TC members. Its scope includes the design, implementation, modelling, theory and application of database systems and their technology. Letters,...
� Adaptive spatial query processing � Spatial indexing � High-dimensional indexing Project Summary This project supports an integrated research and education efforts in the area of database...
Exploiting predicate-window semantics over data streams (2008)
Thanaa M. Ghanem, Walid G. Aref, Ahmed K. Elmagarmid
The continuous sliding-window query model is used widely in data stream management systems where the focus of a continuous query is limited to a set of the most recent tuples. In this paper, we show...
Multimedia Systems VDBMS: A Testbed Facility for Research in Video Database Benchmarking (2008)
Walid G. Aref, Ann C. Catlin, Ahmed K. Elmagarmid, Jianping Fan, Moustafa A. Hammad, F. Ilyas, ...
Abstract Real world video-based applications require database technology that is capable of storing digital video in the form of video databases and providing content-based video search and...
Challenges in Spatio-temporal Stream Query Optimization ∗ ABSTRACT (2008)
Hicham G. Elmongui, Mourad Ouzzani, Walid G. Aref
Simplified technology and low costs have spurred the use of location-detection devices in moving objects. Usually, these devices will send the moving objects ’ location information to a...
Space-partitioning Trees in PostgreSQL: Realization and Performance (2008)
Mohamed Y. Eltabakh, Ramy Eltarras, Walid G. Aref
Many evolving database applications warrant the use of non-traditional indexing mechanisms beyond B+-trees and hash tables. SP-GiST is an extensible indexing framework that broadens the class of...
Discovering Consensus Patterns in Biological Databases (2008)
Mohamed Y. Eltabakh, Walid G. Aref, Mourad Ouzzani, Mohamed H. Ali
Abstract. Consensus patterns, like motifs and tandem repeats, are highly conserved patterns with very few substitutions where no gaps are allowed. In this paper, we present a progressive hierarchical...
Chapter 7 Security and Privacy Challenges of a Digital Government (2008)
Arif Ghafoor, Walid G. Aref, Eugene H. Spafford
Abstract: A digital government can be viewed as an amalgam of heterogeneous information systems that exchange high-volume information among government agencies and public and private sectors engaged...
Distributed Framework for Real-Time Multimedia Object Communication (2008)
Husni Fahmi, Walid G. Aref, Mudassir Latif, Arif Ghafoor
In this paper we highlight major technical requirements for designing and developing future distributed multimedia information system using Internet technology. The key requirements of this system...
Managing biological data using bdbms (2008)
Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref, Ahmed K. Elmagarmid, Yasin Laura-silva, Muhammad U. Arshad, ...
Abstract — We demonstrate bdbms, an extensible database engine for biological databases. bdbms started on the observation that database technology has not kept pace with the specific requirements...
Mohamed F. Mokbel, Walid G. Aref
the date of receipt and acceptance should be inserted later Abstract This paper presents the Scalable On-Line Execution algorithm (SOLE, for short) for continuous and on-line evaluation of concurrent...
Chapter 7 Security and Privacy Challenges of a Digital Government (2007)
Arif Ghafoor, Walid G. Aref, Eugene H. Spafford
Abstract: A digital government can be viewed as an amalgam of heterogeneous information systems that exchange high-volume information among government agencies and public and private sectors engaged...
{ilyas, aref} @ cs. purdue. edu (2007)
Ihab F. Ilyas, Walid G. Aref, Ahmed K. Elmagarmid, Hewlett Packard
Joining ranked inputs is an essential requirement for many database applications, such as ranking search results from multiple search engines and answering multi-feature queries for multimedia...
Elisa Bertino, Moustafa A. Hammad, Walid G. Aref, Ahmed K. Elmagarmid
A novel approach for modeling access control in video databases is presented. The proposed access control mechanism uses both the semantics and the structural composition of video data. The unit of...
Broadcasting Indexed Multidimensional Data (2007)
Chuan-ming Liu, Walid G. Aref, Sunil Prabhakar
The continuous broadcast of data together with an index structure is an eective way of disseminating data in a wireless mobile environment. The index allows a mobile client to tune in only when...
Spectral LPM: An Optimal Locality-Preserving Mapping using the Spectral (not Fractal) Order (2007)
Mohamed F. Mokbel, Walid G. Aref, Ananth Grama
For the past two decades, fractals (e.g., the Hilbert and Peano space-filling curves) have been considered the natural method for providing a locality-preserving mapping. The idea behind a...
Phenomenon-aware stream query processing (2007)
M. H. Ali, Mohamed F. Mokbel, Walid G. Aref
Spatio-temporal data streams that are generated from mobile stream sources (e.g., mobile sensors) experience similar environmental conditions that result in distinct phenomena. Several research...
bdbms: A database management system for biological data (2007)
Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref
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...
bdbms: A database management system for biological data (2007)
Mohamed Y. Eltabakh, Mourad Ouzzani, Walid G. Aref
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...
LUGrid: Update-tolerant grid-based indexing for moving objects (2006)
Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref
Indexing moving objects is a fundamental issue in spatiotemporal databases. In this paper, we propose an adaptive Lazy-Update Grid-based index (LUGrid, for short) that minimizes the cost of object...
Seoul, South Korea in conjuction with VLDB 06 Edited by (2006)
Christophe Claramunt, Ki-joune Li, Simonas Šaltenis, Christian S. Jensen, Mario A. Nascimento, ...
LUGrid: Update-tolerant grid-based indexing for moving objects (2006)
Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref
I11deri11g ~vovirlg objects is afiozdanlental issue ilz slmtioten1l~oral dntnbases. 111 this paper, we propose all ado]>five Lazy-Update Grid-based index (LUGrid, for short) thnt mininlires r11e...
Incremental Evaluation of Sliding-Window Queries over Data Streams (2006)
Thanaa M. Ghanem, Moustafa A. Hammad, Mohamed F. Mokbel, Walid G. Aref, Ahmed K. Elmagarmid
Two research efforts have been conducted to realize sliding-window queries in data stream management systems, namely, query re-evaluation and incremental evaluation. In the query re-evaluation...
Abstract Realizing Privacy-Preserving Features in Hippocratic Databases (2006)
Yasin Laura-silva, Walid Aref, Yasin Laura-silva, Walid G. Aref, Yasin Laura-silva, Walid G. Aref
Preserving privacy has become a crucial requirement for operating a business that manages personal data. Hippocratic databases have been proposed to answer this requirement through a database design...
Challenges in Spatio-temporal Stream Query Optimization ∗ (2006)
Hicham G. Elmongui, Walid G. Aref, Mourad Ouzzani
Simplified technology and low costs have spurred the use of location-detection devices in moving objects. Usually, these devices will send the moving objects ’ location information to a...
Scalability management in sensor-network phenomenabases (2006)
M. H. Ali, Walid G. Aref, Ibrahim Kamel
A phenomenon appears in a sensor network when a group of sensors persist to generate similar behavior over a period of time. PhenomenaBases (or databases of phenomena) are equipped with Phenomena...
Adaptive rank-aware query optimization in relational databases (2006)
Ihab F. Ilyas, Walid G. Aref, Ahmed K. Elmagarmid, Hicham G. Elmongui, Rahul Shah, Jeffrey Scott Vitter
Rank-aware query processing has emerged as a key requirement in modern applications. In these applications, efficient and adaptive evaluation of top-k queries is an integral part of the application...
R-trees with update memos (2006)
Xiaopeng Xiong, Xiaopeng Xiong, Walid G. Aref, Walid G. Aref
The problern of frequerztly clpdating ~nulti-dimensiorzal uzdexes orises i~z man?. location-dependent applications. While the R-tree and its varianrs are one of the donzinant choices for indexing...
The New Casper: Query Processing for Location Services without Compromising Privacy (2006)
Mohamed F. Mokbel, Chi-yin Chow, Walid G. Aref
This paper tackles a major privacy concern in current location-based services where users have to continuously report their locations to the database server in order to obtain the service. For...
Incremental Evaluation of Sliding-Window Queries over Data Streams (2006)
Thanaa M. Ghanem, Moustafa A. Hammad, Mohamed F. Mokbel, Walid G. Aref, Senior Member, Ahmed K. Elmagarmid, ...
Abstract—Two research efforts have been conducted to realize sliding-window queries in data stream management systems, namely, query reevaluation and incremental evaluation. In the query...
Incremental Evaluation of Sliding-Window Queries over Data Streams (2006)
Thanaa M. Ghanem, Moustafa A. Hammad, Mohamed F. Mokbel, Walid G. Aref, Senior Member, Ahmed K. Elmagarmid, ...
Abstract—Two research efforts have been conducted to realize sliding-window queries in data stream management systems, namely, query reevaluation and incremental evaluation. In the query...
Detection and tracking of discrete phenomena in sensor-network databases (2005)
M. H. Ali, Mohamed F. Mokbel, Walid G. Aref, Ibrahim Kamel
This paper introduces a framework for Phenomena Detection and Tracking (PDT, for short) in sensor network databases. Examples of detectable phenomena include the propagation over time of a pollution...
Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref
Location-aware environments are characterized by a large number of objects and a large number of continuous queries. Both the objects and continuous queries may change their locations over time. In...
Sole: Scalable online execution of continuous queries on spatio-temporal data streams (2005)
Mohamed F. Mokbel, Mohamed F. Mokbel, Walid G. Aref, Walid G. Aref
vldb manuscript No. (will be inserted bv the ctlitor)
Spatio-temporal histograms (2005)
Hicham G. Elmongui, Mohamed F. Mokbel, Walid G. Aref
Abstract. This paper presents a framework for building and continuously maintaining spatio-temporal histograms (ST-Histograms, for short). ST-Histograms are used for selectivity estimation of...
Periodicity detection in time series databases (2005)
Mohamed G. Elfeky, Walid G. Aref, Senior Member, Ahmed K. Elmagarmid, Senior Member
Abstract—Periodicity mining is used for predicting trends in time series data. Discovering the rate at which the time series is periodic has always been an obstacle for fully automated periodicity...
SINA: Scalable incremental processing of continuous queries in spatio-temporal databases (2004)
Mohamed F. Mokbel, Xiaopeng Xiong, Walid G. Aref
This paper introduces the Scalable INcremental hash-based Algorithm (SINA, for short); a new algorithm for evaluating a set of concurrent continuous spatio-temporal queries. SINA is designed with two...
Hash-merge Join: A Non-blocking Join algorithm for Producing Fast and Early Join Results (2004)
Mohamed F. Mokbel, Ming Lu, Walid G. Aref
This paper introduces the hash-merge join algorithm (HMJ, for short); a new non-blocking join algorithm that deals with data items from remote sources via unpredictable, slow, or bursty network...
Continuous Query Processing in Spatiotemporal Databases (2004)
Mohamed F. Mokbel, Xiaopeng Xiong, Moustafa A. Hammad, Walid G. Aref
The tremendous increase of cellular phones, GPS-like devices, and RFIDs results in highly dynamic environments where objects as well as queries are continuously moving. In this paper, we present a...
Xingquan Zhu, Xindong Wu, Jianping Fan, Ahmed K. Elmagarmid, Walid G. Aref
Abstract. In this paper, we propose a hierarchical video summarization strategy that explores video content structure to provide the users with a scalable, multilevel video summary. First,...
PLACE: A Query Processor for Handling Real-time Spatio-temporal Data Streams (Demo (2004)
Mohamed F. Mokbel, Xiaopeng Xiong, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar, Moustafa A. Hammad
The emergence of location-aware services calls for new real-time spatio-temporal query processing algorithms that deal with large numbers of mobile objects and queries. In this demo, we present PLACE...
Incremental, Online, and Merge Mining of Partial Periodic Patterns in Time-Series Databases (2004)
Walid G. Aref, Mohamed G. Elfeky, Ahmed K. Elmagarmid, Senior Member
Abstract—Mining of periodic patterns in time-series databases is an interesting data mining problem. It can be envisioned as a tool for forecasting and prediction of the future behavior of...
SINA: Scalable incremental processing of continuous queries in spatio-temporal databases (2004)
Mohamed F. Mokbel, Xiaopeng Xiong, Walid G. Aref
This paper introduces the Scalable INcremental hash-based Algorithm (SINA, for short); a new algorithm for evaluating a set of concurrent continuous spatio-temporal queries. SINA is designed with two...
Scalable Multimedia Disk Scheduling (2004)
Mohamed Mokbel Walid, Walid G. Aref, Khaled Elbassioni, Ibrahim Kamel
A new multimedia disk scheduling algorithm, termed Cascaded-SFC, is presented. The Cascaded-SFC multimedia disk scheduler is applicable in environments where multimedia data requests arrive with...
Using Convolution to Mine Obscure Periodic (2004)
Patterns In One, Mohamed G. Elfeky, Walid G. Aref, Ahmed K. Elmagarmid
The mining of periodic patterns in time series databases is an interesting data mining problem that can be envisioned as a tool for forecasting and predicting the future behavior of time series data....
ClassView: Hierarchical Video Shot Classification, Indexing, and Accessing (2004)
Jianping Fan, Ahmed K. Elmagarmid, Senior Member, Xingquan Zhu, Walid G. Aref, Lide Wu
Recent advances in digital video compression and networks have made video more accessible than ever. However, the existing content-based video retrieval systems still suffer from the following...
VDBMS: A testbed facility for research in video database benchmarking (2004)
Walid G. Aref, Ann Christine Catlin, Ahmed Elmagarmid, Jianping Fan, Moustafa Hammad, Ihab Ilyas, ...
Real-world video-based applications require database technology that is capable of storing digital video in the form of video databases and providing content-based video search and retrieval. Methods...
PLACE: A Query Processor for Handling Real-time Spatio-temporal Data Streams (2004)
Mohamed F. Mokbel, Xiaopeng Xiong, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar, Moustafa A. Hammad
The emergence of location-aware services calls for new real-time spatio-temporal query processing algorithms that deal with large numbers of mobile objects and queries. In this demo, we present PLACE...
Scalable Spatio-temporal Continuous Query Processing for Location-Aware Services (2004)
Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar
The emergence of location-aware services calls for new real-time spatio-temporal query processing algorithms that deal with large numbers of moving objects and large numbers of continuous...
Scalable Spatio-temporal Continuous Query Processing for Location-aware Services (2004)
Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar
The emergence of location-aware services calls for new real-time spatio-temporal query processing algorithms that deal with large numbers of moving objects and large numbers of continuous...
Rank-aware query optimization (2004)
Ihab F. Ilyas, Rahul Shah, Walid G. Aref, Jeffrey Scott, Vitter Ahmed, K. Elmagarmid
Ranking is an important property that needs to be fully supported by current relational query engines. Recently, several rank-join query operators have been proposed based on rank aggregation...
Nile: A Query Processing Engine for Data Streams (2004)
M. A. Hammad, M. F. Mokbel, M. H. Ali, Walid G. Aref, W. G. Aref, A. C. Catlin, ...
Introduction This demonstration presents the design of "STEAM", Purdue Boiler Makers' stream database system that allows for the processing of continuous and snap-shot queries over...
Continuous Query Processing in Spatiotemporal Databases (2004)
Mohamed F. Mokbel, Xiaopeng Xiong, Moustafa A. Hammad, Walid G. Aref
The tremendous increase in the use of cellular phones, GPS-like devices, and RFIDs re-sults in highly dynamic environments where objects as well as queries are continuously mov-ing. In this paper, we...
Scalable Multimedia Disk Scheduling (2004)
Elbassioni, Khaled, Mokbel, Mohamed F., Aref, Walid G., Kamel, Ibrahim
A new multimedia disk scheduling algorithm, termed Cascaded-SFC, is presented. The Cascaded-SFC multimedia disk scheduler is applicable in environments where multimedia data requests arrive with...
Scalable spatio-temporal continuous query processing for location-aware services (2004)
Xiaopeng Xiong, Mohamed F. Mokbel, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar
Real-time spatio-temporal query processing needs to effectively handle a large number of moving objects and continuous spatio-temporal queries. In this paper, we use shared execution as a mechanism...
Stream Window Join: Tracking Moving Objects in Sensor-Network Databases (2003)
Moustafa A. Hammad, Walid G. Aref
The widespread use of sensor networks presents revolutionary opportunities for life and environmental science applications. Many of these applications involve continuous queries that require the...
Supporting top-k join queries in relational databases (2003)
Ihab F. Ilyas, Walid G. Aref, Ahmed K. Elmagarmid
Abstract. Ranking queries, also known as top-k queries, produce results that are ordered on some computed score. Typically, these queries involve joins, where users are usually interested only in the...
Spatio-temporal Access Methods (2003)
Mohamed F. Mokbel, Thanaa M. Ghanem, Walid G. Aref
The rapid increase in spatio-temporal applications calls for new auxiliary indexing structures. A typical spatio-temporal application is one that tracks the behavior of moving objects through...
Supporting top-k join queries in relational databases (2003)
Ihab F. Ilyas, Walid G. Aref, Ahmed K. Elmagarmid
Ranking queries produce results that are ordered on some computed score. Typically, these queries involve joins, where users are usually interested only in the top-k join results. Current relational...
Efficient Execution of Sliding-Window Queries Over Data Streams (2003)
Moustafa Hammad, Walid G. Aref, Michael J. Franklin, Mohamed F. Mokbel, Ahmed K. Elmagarmid
Emerging data stream processing systems rely on windowing to enable on-the-fly processing of continuous queries over unbounded streams. As a result, several recent e#orts have developed window-aware...
Stream Window Join: Tracking Moving Objects in Sensor-Network Databases (2003)
Moustafa A. Hammad, Walid G. Aref, Ahmed K. Elmagarmid
The widespread use of sensor networks presents revolutionary opportunities for life and environmental science applications. Many of these applications involve continuous queries that require the...
Towards Scalable Location-aware Services: Requirements and Research Issues (2003)
Mohamed F. Mokbel, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar
QRK(S T(UVHL64 L?W6XR4Y"J+L"*64H!HL"*N*XZ6H L "4 L?[ 4 !HL"*N*XZ6H 29050 - LT4HLT, T4HLT 23100-4 X^, 060-46520 23100-47570 H 2 LHL]EFc1 16570-46520 L"Pfe*(H!L(...
Supporting Top-k Join Queries in Relational Databases (2003)
Ihab F. Ilyas, Walid G. Aref, Ahmed K. Elmagarmid
Ranking queries produce results that are ordered on some computed score. Typically, these queries involve joins, where users are usually interested only in the top-k join results. Current relational...
Towards scalable location-aware services: Requirements and research issues (2003)
Mohamed F. Mokbel, Walid G. Aref, Susanne E. Hambrusch, Sunil Prabhakar
The emergence of location-aware services calls for new real time spatio-temporal query processing algorithms that deal with large numbers of mobile objects and queries. Online query response is an...
Multiple and Partial Periodicity Mining in Time Series Databases (2002)
Christos Berberidis, Walid G. Aref, Mikhail Atallah, Ioannis Vlahavas, Ahmed K. Elmagarmid
Abstract. Periodicity search in time series is a problem that has been investigated by mathematicians in various areas, such as statistics, economics, and digital signal processing. For large...
On the discovery of weak periodicities in large time series (2002)
Christos Berberidis, Ioannis Vlahavas, Walid G. Aref, Mikhail Atallah, Ahmed K. Elmagarmid
Abstract. The search for weak periodic signals in time series data is an active topic of research. Given the fact that rarely a real world dataset is perfectly periodic, this paper approaches this...
Sunil Prabhakar, Yuni Xia, Dmitri V. Kalashnikov, Walid G. Aref, Susanne E. Hambrusch
AbstractÐMoving object environments are characterized by large numbers of moving objects and numerous concurrent continuous queries over these objects. Efficient evaluation of these queries in...
On the discovery of weak periodicities in large time series (2002)
Christos Berberidis, Ioannis Vlahavas, Walid G. Aref, Ahmed K. Elmagarmid
Abstract. The search for weak periodic signals in time series data is an active topic of research. Given the fact that rarely a real world dataset is perfectly periodic, this paper approaches this...
A Video Database Management System for Advancing Video Database Research (2002)
Walid G. Aref, Ann C. Catlin, Jianping Fan, Ahmed K. Elmagarmid, Moustafa A. Hammad, Ihab F. Ilyas, ...
The most useful environments for advancing research and development in video databases are those that provide complete video database management, including (1) video preprocessing for content...
Scalable QoS- aware disk scheduling (2002)
Walid G. Aref, Khaled El-bassyouni, Ibrahim Kame, Mohamed F. Mokbel
A r~ew quali ~ of se1-1,ice (QoS) nc1:rtt.e rli.tk sched~rlir~g 01gorirhrn is preserired. 11 is applical~le irl ert~~irarlrnerirs where rlara requests art-i1.e 1virl1 dt'fferer~r QoS...
S. Prabhakar, Y. Xia, D. Kalashnikov, Walid G. Aref, W. G. Aref, S. Hambrusch
Moving object environments are characterized by large numbers of moving objects and numerous concurrent continuous queries over these objects. Efficient evaluation of these queries in response to the...
A framework for supporting the class of space-partitioning trees (2001)
Emerging database applications require the use of new indexing structures beyond B-trees and R-trees. Examples are the k-D tree, the trie, the quadtree, and their variants. They are often proposed as...
An extensible index for spatial databases (2001)
Emerging database applications require the use of new indexing structures beyond B-trees and R-trees. Examples are the k-D tree, the trie, the quadtree, and their variants. They are often proposed as...
An extensible index for spatial databases (2001)
Emerging database applications require the use of new indexing structures beyond B-trees and R-trees. Examples are the k-D tree, the trie, the quadtree, and their variants. They are often proposed as...
Digital government security infrastructure design challenges (2001)
James Joshi, Arif Ghafoor, Walid G. Aref, Eugene H
Designing security systems for a digital government’s multidomain environment requires a careful balancing act between providing convenient access and carefully monitoring permissions. Information...
Query processing in broadcasted spatial index trees (2001)
Susanne Hambrusch, Chuan-ming Liu, Walid G. Aref, Sunil Prabhakar
Abstract. The broadcasting of spatial data together with an index structure is an eective way of disseminating data in a wireless mobile environment. Mobile clients requesting data tune into a...
An extensible index for spatial databases (2001)
Emerging database applications require the use of new indexing structures beyond B-trees and R-trees. Examples are the k-D tree, the trie, the quadtree, and their variants. They are often proposed as...
Query processing in broadcasted spatial index trees (2001)
Susanne Hambrusch, Chuan-ming Liu, Walid G. Aref, Sunil Prabhakar
Abstract. The broadcasting of spatial data together with an index structure is an eective way of disseminating data in a wireless mobile environment. Mobile clients requesting data tune into a...
Disk Scheduling in Video Editing Systems (2001)
Walid G. Aref, Ibrahim Kamel, Shahram Ghandeharizadeh, Shahram Gh
Modern video servers support both video-on-demand and non-linear editing applications. Video-on-demand servers enable the user to view video clips or movies from a video database, while non-linear...
MultiView: Multilevel video content representation and retrieval (2001)
Jianping Fan, Walid G. Aref, Ahmed K. Elmagarmid, Mohand-said Hacid, Mirette Marzouk, ...
In this article, several practical algorithms are proposed to support content-based video analysis, modeling, representation, summarization, indexing, and access. First, a multilevel video database...
W.G.: Window query processing in linear quadtrees (2001)
Ashraf Aboulnaga, Walid G. Aref
The linear quadtree is a spatial access method that is built by decomposing the spatial objects in a database into quadtree blocks and storing these quadtree blocks in a B-tree. It is very useful for...
Automatic Image Segmentation by Integrating Color-Edge Extraction And Seeded Region Growing (2001)
Jianping Fan, Ahmed K. Elmagarmid, Senior Member, Walid G. Aref
We propose a new automatic image segmentation method. Color edges in an image are first obtained automatically by combining an improved isotropic edge detector and a fast entropic thresholding...
An inexpensive, scalable, and open-architecture media server (1999)
Walid G. Aref, David Braun, Dennis Bushmitch, Ibrahim Kamel, Sarit Mukherjee
An inexpensive scalable architecture for a multimedia server is presented. A detailed view of its software and hardware components is explained, as well as its performance. Results indicate linear...
Automatic disks: The building block for a scalable distributed file system (1999)
Cuneyt Akinlar, Walid G. Aref, Ibrahim Kamel, Sarit Mukherjee
Repository for multimedia data differs from that of the traditional text-based data both in storage space and streaming bandwidth requirements. Thus, the file systems used in multimedia environment...
On local heuristics to speed up polygon-polygon intersection tests (1999)
The polygon-polygon intersection operation is CPU-intensive. Many data structures look into decomposing the polygons into multiple yet simple pieces to speed up the polygon-polygon intersection...
E cient Window Block Retrieval in Quadtree-Based Spatial Databases 1 (1997)
An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving all of the quadtree blocks in the underlying spatial database that cover the quadtree...
Efficient Window Block Retrieval in Quadtree-Based Spatial Databases (1996)
An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving all of the quadtree blocks in the underlying spatial database that cover the quadtree...
A Window Retrieval Algorithm for Spatial Databases Using Quadtrees (1995)
An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving the covering blocks in the underlying spatial database. It works by decomposing the...
Spatial data models and query processing (1995)
An overview is presented of the issues in building spatial databases. The focus is on data models and query processing. Query optimization in a spatial environment is also brie y discussed.
Spatial Data Models and Query Processing (1994)
An overview is presented of the issues in building spatial databases. The focus is on data models and query processing. Query optimization in a spatial environment is also briefly discussed. Keywords...
Hashing by proximity to process duplicates in spatial databases (1994)
In a spatial database, an object may extend arbitrarily in space. As a result, many spatial data structures (e.g., the quadtree, the cell tree, the R +-tree) represent an object by partitioning it...
Extending a DBMS with Spatial Operations 1 (1991)
A central problem in modern database design is how to resolve spatial operations with normal database operations in an extended relational database environment. A data architecture that matches the...
An Approach to Information Management in Geographical Applications (1990)
The design of an integrated system is described for combining spatial and nonspatial attribute data to allow fast query handling. By fast it is meant that search queries can be executed in...
An Approach to Information Management in Geographical Applications (1990)
The design of an integrated system is described for combining spatial and nonspatial attribute data to allow fast query handling. By fast it is meant that search queries can be executed in...
[7] Akyurek, Sedat, and Kenneth Salem, “Placing Replicated Data to Reduce Seek (1988)
Walid G. Aref, Ibrahim Kamel, Sarit Mukherjee, Kenneth Salem, Adaptive Block Rearrangement
[5] ANSI/IEEE 802.3 (ISO/DIS 8802/3), “Carrier sense multiple access with collision detect (CSMA/CD) access method and physical layer specifications”, IEEE Press,