Department of Electrical Engineering and Computer Science, Case Western Reserve University, Cleveland, OH
Wen-Chi Hou, Gultekin Özsoyoglu, Baldeo K. Taneja
Proceedings of the Seventh ACM SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 1988 – PODS
Present database systems process all the data related to a query before giving out responses. As a result, the size of the data to be processed becomes excessive for real-time/time-constrained environments. A new methodology is needed to cut down ...
Wen-Chi Hou, Gultekin Özsoyoglu, Baldeo K. Taneja
1989 ACM SIGMOD International Conference on Management of Data, 1989 – SIGMOD
We consider those database environments in which queries have strict timing constraints, and develop a time-constrained query evaluation methodology. For aggregate relational algebra queries, we describe a time constrained query evaluation algorithm. ...
Wen-Chi Hou, Gultekin Özsoyoglu, Erdogan Dogdu
1991 ACM SIGMOD International Conference on Management of Data, 1991 – SIGMOD
ABSTRAGT An error-constrained COUNT query in relational algebra is of the form “Estimate COUNT(E), where E is a relational algebra expression, such that the error in the estimate is at most en. The general approach is to evaluate an estimator for ...
Gultekin Özsoyoglu, Z. Meral Özsoyoglu, Victor Matos
ACM Transactions on Database Systems, vol. 12,no. 4,1987 – TODS
In commercial network database management systems, set-valued fields and aggregate functions are commonly supported. However, the relational database model, as defined by Codd, does not include set-valued attributes or aggregate functions. Recently, ...
Wen-Chi Hou, Gultekin Özsoyoglu, Erdogan Dogdu
ACM SIGMOD Record, vol. 20,no. 2,1991 – SIGMOD_Record
ABSTRAGT An error-constrained COUNT query in relational algebra is of the form “Estimate COUNT(E), where E is a relational algebra expression, such that the error in the estimate is at most en. The general approach is to evaluate an estimator for ...
Wen-Chi Hou, Gultekin Özsoyoglu, Baldeo K. Taneja
ACM SIGMOD Record, vol. 18,no. 2,1989 – SIGMOD_Record
We consider those database environments in which queries have strict timing constraints, and develop a time-constrained query evaluation methodology. For aggregate relational algebra queries, we describe a time constrained query evaluation algorithm. ...
Gultekin Özsoyoglu, Richard T. Snodgrass
IEEE Transactions on Knowledge and Data Engineering, vol. 7,no. 4,1995 – TKDE
Abstract—A temporal database contains time-varying data. In a real-time database transactions have deadlines or timing constraints. In this paper we review the substantial research in these two previously separate areas. First we characterize the ...
Francis Yuk-Lun Chin, Gultekin Özsoyoglu
IEEE Transactions on Software Engineering, vol. 8,no. 6,1982 – TSE
Wen-Chi Hou, Gultekin Özsoyoglu
ACM Transactions on Database Systems, vol. 16,no. 4,1991 – TODS
This paper discusses the estimation of COUNT(E) queries by sampling, where E is an arbitrary relational algebra expression. Consistent and unbiased statistical estimators for COUNT(E) are proposed without any assumptions on the distributions of ...
Gultekin Özsoyoglu, Kaizheng Du, A. Tjahjana, Wen-Chi Hou, D. Y. Rowland