Network


Latest external collaboration on country level. Dive into details by clicking on the dots.

Hotspot


Dive into the research topics where Peter Z. Revesz is active.

Publication


Featured researches published by Peter Z. Revesz.


International Journal of Algebra and Computation | 1997

On the Semantics of Arbitration

Peter Z. Revesz

Revision and update operators add new information to some old information represented by a logical theory. Katsuno and Mendelzon show that both revision and update operators can be characterized as accomplishing a minimal change in the old information to accommodate the new information. Arbitration operators add two or more weighted informations together where the weights indicate the relative importance of the informations rather than a strict priority. This paper shows that arbitration operators can be also characterized as accomplishing a minimal change. The operator of model-fitting is also defined and analyzed in the paper.


symposium on principles of database systems | 1993

On the semantics of theory change: arbitration between old and new information

Peter Z. Revesz

Katsuno and Mendelzon divide theory change, the problem of adding new information to a logical theory, into two types: revision and update. We propose a third type of theory change: arbitration. The key idea is the following: the new information is considered neither better nor worse than the old information represented by the logical theory. The new information is simply one voice against a set of others already incorporated into the logical theory. From this follows that arbitration should be commutative. First we define arbitration by a set of postulates and then describe a model-theoretic characterization of arbitration for the case of propositional logical theories. We also study weighted arbitration where different models of a theory can have different weights.


symposium on principles of database systems | 1990

Constraint query languages (preliminary report)

Paris C. Kanellakis; Gabriel M. Kuper; Peter Z. Revesz

We discuss the relationship between constraint programming and database query languages. We show that bottom-up, efficient, declarative database programming can be combined with efficient constraint solving. The key intuition is that the generalization of a ground fact, or tuple, is a conjunction of constraints. We describe the basic Constraint Query Language design principles, and illustrate them with four different classes of constraints: Polynomial, rational order, equality, and Boolean constraints.


international conference on database theory | 1993

A closed-form evaluation for Datalog queries with integer (gap)-order constraints

Peter Z. Revesz

We provide a generalization of Datalog based on generalizing databases with the addition of integer-order constraints to relational tuples. For Datalog queries with integer-order constraints we show that there is a closed-form evaluation. We also show that the tuple recognition problem can be done in PTIME in the size of the (generalized) database, assuming that the size of the constants in the query is logarithmic in the size of the database. Note that the absence of negation is critical. Datalog queries with integer-order constraints can express any Turing-computable function.


Geoinformatica | 1999

Constraint-based Interoperability of Spatiotemporal Databases*

Jan Chomicki; Peter Z. Revesz

We propose constraint databases as an intermediate level facilitating the interoperability of spatiotemporal data models. Constraint query languages are used to express translations between different data models. We illustrate our approach in the context of a number of temporal, spatial, and spatiotemporal data models.


Proteins | 2006

Comparison of protein active site structures for functional annotation of proteins and drug design.

Robert Powers; Jennifer C. Copeland; Katherine Germer; Kelly A. Mercier; Viswanathan Ramanathan; Peter Z. Revesz

Rapid and accurate functional assignment of novel proteins is increasing in importance, given the completion of numerous genome sequencing projects and the vastly expanding list of unannotated proteins. Traditionally, global primary‐sequence and structure comparisons have been used to determine putative function. These approaches, however, do not emphasize similarities in active site configurations that are fundamental to a proteins activity and highly conserved relative to the global and more variable structural features. The Comparison of Protein Active Site Structures (CPASS) database and software enable the comparison of experimentally identified ligand‐binding sites to infer biological function and aid in drug discovery. The CPASS database comprises the ligand‐defined active sites identified in the protein data bank, where the CPASS program compares these ligand‐defined active sites to determine sequence and structural similarity without maintaining sequence connectivity. CPASS will compare any set of ligand‐defined protein active sites, irrespective of the identity of the bound ligand. Proteins 2006.


Computers, Environment and Urban Systems | 2004

Interpolation Methods for Spatio-Temporal Geographic Data

Lixin Li; Peter Z. Revesz

We consider spatio-temporal interpolation of geographic data using both the reduction method, which treats time as an independent dimension, and the extension method, which treats time as equivalent to a spatial dimension. We adopt both 2-D and 3-D shape functions from finite element methods for the spatio-temporal interpolation of 2-D spatial and 1-D temporal data sets. We also develop new 4-D shape functions and use them for the spatio-temporal interpolation of 3-D spatial and 1-D temporal data sets. Using an actual real estate data set with house prices, we compare these methods with other spatio-temporal interpolation methods based on inverse distance weighting and kriging. The comparison criteria include interpolation accuracy, error-proneness to time aggregation, invariance to scaling on the coordinate axes, and the type of constraints used in the representation of the interpolated data. Our experimental results show that the extension method based on shape functions is the most accurate and the overall best spatio-temporal interpolation method. New color rendering algorithms are also developed for the visualization of time slices of the interpolated spatio-temporal data. We show some visualization results of the real estate data set including the vertical profile of house prices.


international symposium on temporal representation and reasoning | 1999

A geometric framework for specifying spatiotemporal objects

Jan Chomicki; Peter Z. Revesz

We present a framework for specifying spatiotemporal objects using spatial and temporal objects, and a geometric transformation. We define a number of classes of spatiotemporal objects and study their closure properties.


international conference on database theory | 1990

A Closed Form for Datalog Queries with Integer Order

Peter Z. Revesz

The use of constraints within logic programming and within database languages promises interesting new applications. We show that Datalog queries with simple integer order constraints can be evaluated bottom-up in closed form over generalized databases.


Lecture Notes in Computer Science | 1997

Constraint-Based Interoperability of Spatiotemporal Databases

Jan Chomicki; Peter Z. Revesz

We propose constraint databases as an intermediate level facilitating the interoperability of spatiotemporal data models. Constraint query languages are used to express translations between different data models. We illustrate our approach in the context of a number of temporal, spatial and spatiotemporal data models.

Collaboration


Dive into the Peter Z. Revesz's collaboration.

Top Co-Authors

Avatar
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Lixin Li

University of Nebraska–Lincoln

View shared research outputs
Top Co-Authors

Avatar

Rui Chen

University of Nebraska–Lincoln

View shared research outputs
Top Co-Authors

Avatar

Scot Anderson

University of Nebraska–Lincoln

View shared research outputs
Top Co-Authors

Avatar

Thomas Triplet

University of Nebraska–Lincoln

View shared research outputs
Top Co-Authors

Avatar
Top Co-Authors

Avatar

Robert Powers

University of Nebraska–Lincoln

View shared research outputs
Top Co-Authors

Avatar

Shasha Wu

Spring Arbor University

View shared research outputs
Top Co-Authors

Avatar

Mark A. Griep

University of Nebraska–Lincoln

View shared research outputs
Researchain Logo
Decentralizing Knowledge