Reducing Network Energy Consumption via Sleeping and Rate-Adaptation (2009)
Sergiu Nedevschi, Lucian Popa, Gianluca Iannaccone, Sylvia Ratnasamy, David Wetherall
We present the design and evaluation of two forms of power management schemes that reduce the energy consumption of networks. The first is based on putting network components to sleep during idle...
Interactive Generation of Integrated Schemas (2009)
Laura Chiticariu, Phokion G. Kolaitis, Lucian Popa
Schema integration is the problem of creating a unified target schema based on a set of existing source schemas that relate to each other via specified correspondences. The unified schema gives a...
their valuable feedback. A Policy-aware Switching Layer for Data Centers (2009)
Dilip Antony Joseph, Arsalan Tavakoli, Ion Stoica, Gautam Altekar, Ganesh Ananthanarayanan, Rodrigo Fonseca, ...
personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the...
ABSTRACT Entirely Declarative Sensor Network Systems (2008)
David Chu, Arsalan Tavakoli, Lucian Popa, Joseph Hellerstein
The database and sensor network community have both recognized the utility of SQL for interfacing with sensor network systems. Recently there have been proposals to construct Internet protocols...
Abstract Reducing Network Energy Consumption via Sleeping and Rate-Adaptation (2008)
Sergiu Nedevschi, Lucian Popa, Gianluca Iannaccone, Sylvia Ratnasamy, David Wetherall
We present the design and evaluation of two forms of power management schemes that reduce the energy consumption of networks. The first is based on putting network components to sleep during idle...
Tomas: a system for adapting mappings while schemas evolve (2008)
Yannis Velegrakis, Renée J. Miller, Lucian Popa, John Mylopoulos
A broad variety of data is available on the Web in distinct heterogeneous sources, stored under different formats: database formats (relational), document formats (SGML/XML), browser formats (HTML),...
Semi-Automatic Schema Integration in Clio ∗ (2008)
Laura Chiticariu, Mauricio A. Hernández, Phokion G. Kolaitis, Lucian Popa
Schema integration is the problem of finding a unified representation, called the integrated schema, from a set of source schemas that are related to each other. The relationships between the source...
ToMAS: Mapping Adaptation Under Evolving Schemas ∗ (2008)
Yannis Velegrakis, Renée J. Miller, Lucian Popa, John Mylopoulos
To achieve interoperability, modern information systems and e-commerce applications use mappings to translate data from one representation to another. In dynamic environments like the Web, data...
EII and ETL Unification---It’s about Time! (2008)
Howard Ho, Joint Mauricio Hern, Lucian Popa
Integration, transformation and exchange of data are well known and fast growing problems. Solving the integration problem typically requires: (1) understanding and reconciling the differences...
Semi-Automatic Schema Integration in Clio (2008)
Laura Chiticariu, Mauricio A. Hernández, Phokion G. Kolaitis, Lucian Popa
Schema integration is the problem of finding a unified representation, called the integrated schema, from a set of source schemas that are related to each other. The relationships between the source...
Haifeng Jiang, Howard Ho, Lucian Popa, Wook-shin Han
Clio is an existing schema-mapping tool that provides user-friendly means to manage and facilitate the complex task of transformation and integration of heterogeneous data such as XML over the Web or...
Data Integration, Where Does, Time Go, Len Seligman, Arnon Rosenthal, Paul Lehner, ...
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...
ABSTRACT Entirely Declarative Sensor Network Systems (2008)
David Chu, Arsalan Tavakoli, Lucian Popa, Joseph Hellerstein
The database and sensor network community have both recognized the utility of SQL for interfacing with sensor network systems. Recently there have been proposals to construct Internet protocols...
On Preserving Mapping Consistency under Schema Changes (2008)
Yannis Velegrakis, Renee Miller, Lucian Popa
To achieve interoperability, modern information systems and e-commerce applications use mappings to translate data from one representation to another. In dynamic environments like the Web, data...
A Pc Chase, Lucian Popa, Val Tannen
PC stands for path-conjunctive, the name of a class of queries and dependencies that we define over complex values with dictionaries. This class includes the relational conjunctive queries and...
ABSTRACT Data Exchange: Getting to the Core (2007)
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. Given a source...
Data Exchange: Semantics and Query Answering � Abstract (2007)
Ronald Fagin, Phokion G. Kolaitis, Renée J. Miller, Lucian Popa
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this paper, we...
Presented to the Faculties of the University of Pennsylvania (2007)
Lucian Popa, Val Tannen, Val Tannen, Jonathan Crabtree, Susan Davidson, Alin Deutsch, ...
I am indebted to Val Tannen, my advisor. This dissertation would not have been possible without his invaluable ideas, support, and advice. His deep insight into both fields of databases and...
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Renée J. Miller
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this paper, we...
Mary Fernandez, Lucian Popa, Dan Suciu
Abstract. Several researchers have considered integrating multiple unstructured, semi-structured, and structured data sources by modeling all sources as edge labeled graphs. Data in this model is...
Ren'ee J. Miller, Mauricio A. Hern'andez, Laura M. Haas, Lingling Yan, Ronald Fagin, ...
Clio is a system for managing and facilitating the complex tasks of heterogeneous data transformation and integration. In Clio, we have collected together a powerful set of data management techniques...
Quasi-inverses of schema mappings (2007)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Wang-chiew Tan
Schema mappings are high-level specifications that describe the relationship between two database schemas. Two operators on schema mappings, namely the composition operator and the inverse operator,...
I.: Balancing traffic load in wireless networks with curveball routing (2007)
Lucian Popa, Afshin Rostamizadeh, Richard M. Karp, Christos Papadimitriou
We address the problem of balancing the traffic load in multi-hop wireless networks. We consider a point-to-point communicating network with a uniform distribution of source-sink pairs. When routing...
MALIGNANT MELANOMA OF THE HEAD SKIN (2006)
Camelia Tamas, Doinita Radulescu, Lucian Popa, C. Tarasi, Cristina Stanescu, R. Nita
Malignant melanoma (MM) is known as a tumor with high malignancy. The development of a melanoma on the head skin is even more severe, as prognosis, because of the limitted possibilities for large...
The design and implementation of a declarative sensor network system (2006)
David Chu, Lucian Popa, Arsalan Tavakoli, Joseph M. Hellerstein, Philip Levis, Scott Shenker
Sensor networks are notoriously difficult to program, given that they encompass the complexities of both distributed and embedded systems. To address this problem, we present the design and...
The design and implementation of a declarative sensor network system (2006)
David Chu, Lucian Popa, Arsalan Tavakoli, Joseph M. Hellerstein, Philip Levis, Scott Shenker
Sensor networks are notoriously difficult to program, given that they encompass the complexities of both distributed and embedded systems. To address this problem, we present the design and...
Inverting Schema Mappings (2006)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa
Schema mappings are high-level specifications that describe the relationship between two database schemas. Two operators on schema mappings, namely the composition operator and the inverse operator,...
The design and implementation of a declarative sensor network system (2006)
David Chiyuan Chu, David Chu, Lucian Popa, Lucian Popa, Arsalan Tavakoli, Arsalan Tavakoli, ...
personal or classroom use is granted without fee provided that copies are not made or distributed for profit or commercial advantage and that copies bear this notice and the full citation on the...
David Chu, Lucian Popa, Arsalan Tavakoli, Joseph M. Hellerstein, Philip Levis, Scott Shenker
Sensor networks are notoriously difficult to program, given that they encompass the complexities of both distributed and embedded systems. To address this problem, we present the design and...
SURGICAL RECONSTRUCTION IN SCALP DEFECTS (2005)
Camelia Tamas, Lucian Popa, Dana Turliuc, C. Morosanu, Madalina Lazar, E. Vasilica, ...
In scalp injuries the choice between use of a transposition flap, a rotation flap or other types of plasty is most often influenced by the size and nature of the defect. The study refers to 14...
Semantic Adaptation of Schema Mappings when Schemas Evolve (2005)
Cong Yu Lucian, Cong Yu, Lucian Popa
Schemas evolve over time to accommodate the changes in the information they represent. Such evolution causes invalidation of various artifacts depending on the schemas, such as schema mappings. In a...
Semantic Adaptation of Schema Mappings when Schemas Evolve (2005)
Cong Yu Lucian, Cong Yu, Lucian Popa
Schemas evolve over time to accommodate the changes in the information they represent. Such evolution causes invalidation of various artifacts depending on the schemas, such as schema mappings. In a...
Clio Grows Up: From Research Prototype to Industrial Tool (2005)
Laura M. Haas, Mauricio A. Hernández, Lucian Popa
Clio, the IBM Research system for expressing declarative schema mappings, has progressed in the past few years from a research prototype into a technology that is behind some of IBM’s mapping...
Semantic Adaptation of Schema Mappings when Schemas Evolve (2005)
Schemas evolve over time to accommodate the changes in the information they represent. Such evolution causes invalidation of various artifacts depending on the schemas, such as schema mappings. In a...
Clio Grows Up: From Research Prototype to Industrial Tool (2005)
Laura M. Haas, Mauricio A. Hernández, Lucian Popa, Mary Roth, Howard Ho
Clio, the IBM Research system for expressing declarative schema mappings, has progressed in the past few years from a research prototype into a technology that is behind some of IBM’s mapping...
Preserving Mapping Consistency under Schema Changes (2004)
Yannis Velegrakis, Renée J. Miller, Lucian Popa
Abstract. In dynamic environments like the Web, data sources may change not only their data but also their schemas, their semantics, and their query capabilities. When a mapping is left inconsistent...
Composing Schema Mappings: (2004)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Wang-chiew Tan
this paper, we give a rigorous semantics to the composition of schema mappings and investigate the definability and computational complexity of the composition of two schema mappings. We first study...
Composing schema mappings: Second-order dependencies to the rescue (2004)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Wang-chiew Tan
A schema mapping is a specification that describes how data structured under one schema (the source schema) is to be transformed into data structured under a different schema (the target schema). A...
Composing schema mappings: Second-order dependencies to the rescue (2004)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa, Wang-chiew Tan
A schema mapping is a specification that describes how data structured under one schema (the source schema) is to be transformed into data structured under a different schema (the target schema). A...
Using Code Collection to Support Large Applications on Mobile Devices (2004)
The progress of mobile device technology unfolds a new spectrum of applications that challenges conventional infrastructure models. Most of these devices are perceived by their users as...
Data exchange: Semantics and query answering (2003)
Ronald Fagin, Phokion G. Kolaitis, Renée J. Miller, Lucian Popa
Abstract. Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this...
Mapping adaptation under evolving schemas (2003)
Yannis Velegrakis, Renée J. Miller, Lucian Popa
To achieve interoperability, modern information systems and e-commerce applications use mappings to translate data from one representation to another. In dynamic environments like the Web, data...
Data exchange: Semantics and query answering (2003)
Ronald Fagin, Phokion G. Kolaitis, Renée J. Miller, Lucian Popa
Abstract. Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this...
Data Exchange: Getting to the Core (2003)
Ronald Fagin Ibm, Ronald Fagin, Lucian Popa, Phokion G. Kolaitis
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. Given a source...
Data Exchange: Getting to the Core (2003)
Ronald Fagin Ibm, Ronald Fagin, Lucian Popa, Phokion G. Kolaitis
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. Given a source...
Data Exchange: Getting to the Core (2003)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa
this paper appeared in Proc. 2003 ACM Symposium of Principles of Database Systems, San Diego, pp. 90--101
Data exchange: Getting to the core (2003)
Ronald Fagin, Phokion G. Kolaitis, Lucian Popa
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. Given a source...
Adapting Mappings in Frequently Changing Environments (2003)
Yannis Velegrakis Renee, Yannis Velegrakis, Renee J. Miller, Lucian Popa
To achieve interoperability, modern information systems and e-commerce applications use mappings to translate data from one representation to another. In dynamic environments like the Web, data...
Andritsos, Periklis, Fagin, Ronald, Fuxman, Ariel, Haas, Laura M., Hernandez, Mauricio A., Ho, Howard, ...
Andritsos, Periklis, Fagin, Ronald, Fuxman, Ariel, Haas, Laura M., Hernandez, Mauricio A., Ho, Howard, ...
Mapping XML and Relational Schemas with Clio (2002)
Popa, Lucian, Hernandez, Mauricio A., Velegrakis, Yannis, Miller, Renée J., Naumann, Felix, Ho, Howard
Mapping XML and Relational Schemas with Clio (2002)
Popa, Lucian, Hernandez, Mauricio A., Velegrakis, Yannis, Miller, Renée J., Naumann, Felix, Ho, Howard
Lucian Popa, Yannis Velegrakis, Renée J. Miller, Mauricio A. Hernández, Ronald Fagin
We present a novel framework for mapping between any combination of XML and relational schemas, in which a high-level, userspecified mapping is translated into semantically meaningful queries that...
Data Exchange: Semantics and Query Answering (2002)
Fagin Ronald, Phokion G. Kolaitis, Renee J. Miller, Lucian Popa
Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this paper, we...
Lucian Popa, Yannis Velegrakis, Renée J. Miller, Mauricio A. Hernández, Ronald Fagin
We present a novel framework for mapping between any combination of XML and relational schemas, in which a high-level, userspecified mapping is translated into semantically meaningful queries that...
Mapping XML and Relational Schemas with Clio (2002)
Lucian Popa, Mauricio A. Hernández, Yannis Velegrakis, Renée J. Miller, Felix Naumann Y, Howard Ho Y
Merging and coalescing data from multiple and diverse sources into different data formats continues to be an important problem in modern information systems. Schema Matching, the process of matching...
Deutsch, Alin, Popa, Lucian, Tannen, Val
We have previously proposed chase and backchase as a novel method for using materialized views and integrity constraints in query optimization. In this paper, we show that the method is usable in...
Object/relational query optimization with chase and backchase (2001)
Traditionally, query optimizers assume a direct mapping from the logical entities modeling the data (e.g. relations) and the physical entities storing the data (e.g. indexes), each physical entity...
The Clio project: managing heterogeneity (2001)
Renee J. Miller, Mauricio A. Hernandez, Laura M. Haas, Ronald Fagin, Lucian Popa, ...
Clio is a system for managing and facilitating the complex tasks of heterogeneous data transformation and integration. In Clio, we have collected together a powerful set of data management techniques...
Popa, Lucian, Deutsch, Alin, Sahuguet, Arnaud, Tannen, Val
In a previous paper we proposed a novel method for generating alternative query plans that uses chasing (and back-chasing) with logical constraints. The method brings together use of indexes, use of...
Object/relational query optimization with chase and backchase (2000)
Traditionally, query optimizers assume a direct mapping from the logical entities modeling the data (e.g. relations) and the physical entities storing the data (e.g. indexes), each physical entity...
Lucian Popa, Alin Deutsch, Arnaud Sahuguet, Val Tannen
In a previous paper we proposed a novel method for generating alternative query plans that uses chasing (and back-chasing) with logical constraints. The method brings together use of indexes, use of...
Lucian Popa, Alin Deutsch, Arnaud Sahuguet, Val Tannen
In a previous paper we proposed a novel method for generating alternative query plans that uses chasing (and back-chasing) with logical constraints. The method brings together use of indexes, use of...
Physical Data Independence, Constraints and Optimization with Universal Plans (1999)
Deutsch, Alin, Popa, Lucian, Tannen, Val
We present an optimization method and al gorithm designed for three objectives: physi cal data independence, semantic optimization, and generalized tableau minimization. The method relies on...
An Equational Chase for Path-Conjunctive Queries, Constraints, and Views (1999)
We consider the class of path-conjunctive queries and constraints (dependencies) defined over complex values with dictionaries. This class includes the relational conjunctive queries and embedded...
Popa, Lucian, Deutsch, Alin, Sahuguet, Arnaud, Tannen, Val
In a previous paper* we proposed a novel method for generating alternative query plans that uses chasing (and back-chasing) with logical constraints. The method brings together use of indexes, use of...
Physical data independence, constraints, and optimization with universal plans (1999)
Alin Deutsch, Lucian Popa, Val Tannen
We present an optimization method and algorithm designed for three objectives: physical data independence, semantic optimization, and generalized tableau minimization. The method relies on...
An Equational Chase for Path-Conjunctive Queries, Constraints, and Views (1999)
Abstract. We consider the class of path-conjunctive queries and constraints (dependencies) defined over complex values with dictionaries. This class includes the relational conjunctive queries and...
Physical Data Independence, Constraints, and Optimization With Universal Plans (1999)
Alin Deutsch, Lucian Popa, Val Tannen
We present an optimization method and al# gorithm designed for three objectives# physi# cal data independence# semantic optimization# and generalized tableau minimization. The method relies on...
PC stands for path-conjunctive, the name of a class of queries and dependencies that we define over complex values with dictionaries. This class includes the relational conjunctive queries and...
Chase and Axioms for PC Queries and Dependencies (1998)
This report is the extended version of [PT99] and while they are some overlapping parts (mainly the results) we don't repeat here some of the examples given in [PT99], even though we frequently...
Querying an Object-Oriented Database Using CPL (1997)
Davidson, Susan B., Hara, Carmem, Popa, Lucian
The Collection Programming Language is based on a complex value model of data and has successfully been used for querying transforming and integrating data from a wide variety of structured data...
A Structure-Based Approach to Querying Semi-Structured Data (1997)
Mary Fernandez, Lucian Popa, Dan Suciu
. Several researchers have considered integrating multiple unstructured, semi-structured, and structured data sources by modeling all sources as edge labeled graphs. Data in this model is...
Input/Output: Algorithms and Architectures (1997)
Modern processors are improving their speed at a very fast rate. Memory design technologies try to keep pace with rapid evolution of processors, and combined with caching techniques, they partly...
Querying an Object-Oriented Database Using CPL (1997)
Susan Davidson, Carmem Hara, Lucian Popa
The Collection Programming Language (CPL) is based on a complex value model of data, and has successfully been used for querying, transforming and integrating data from a wide variety of structured...
Mapping Adaptation under Evolving Schemas
Yannis Velegrakis Renee, Yannis Velegrakis, Renée J. Miller, Lucian Popa
To achieve interoperability, modern information systems and e-commerce applications use mappings to translate data from one representation to another. In dynamic environments like the Web, data...