Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics Commons™
Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Completeness (1)
- Database integration (1)
- Distinctness rules (1)
- Distributed databases (1)
- Entity identification (1)
-
- Extended key (1)
- Extended key attribute values (1)
- Federated Autonomous Databases (1)
- Heterogeneous databases (1)
- ILFD (1)
- Instance level (1)
- Instance level functional dependencies (1)
- Integrated access (1)
- Integrated world (1)
- Object instances (1)
- Real-world entities (1)
- Schema level heterogeneity (1)
- Semantic constraint information (1)
- Tuple (1)
Articles 1 - 15 of 15
Full-Text Articles in Physical Sciences and Mathematics
Asynchronous Transaction Commitment In Federated Database Systems, San-Yih Hwang, Ee Peng Lim, Jaideep Srivastava
Asynchronous Transaction Commitment In Federated Database Systems, San-Yih Hwang, Ee Peng Lim, Jaideep Srivastava
Research Collection School Of Computing and Information Systems
We propose a new (and restricted) model for global transactions which allows asynchronous commitment of subtransactions. Our model requires each global transaction to have a fixed structure with update to the data in at most one database. Based on this transaction model, we present two concurrency control algorithms, namely Asynchronous Site Graph and Asynchronous VirtGlobalSG, which employ asynchronous commitment and achieve global serializability. Compared to other proposed algorithms, our algorithms employ asynchronous commitment so as to increase transaction performance. Furthermore, our algorithms do not put restrictions on transaction data access or local histories.
Multiple Query Optimization With Depth-First Branch-And-Bound, Ahmet Cosar, Ee Peng Lim, Jaideep Srivastava
Multiple Query Optimization With Depth-First Branch-And-Bound, Ahmet Cosar, Ee Peng Lim, Jaideep Srivastava
Research Collection School Of Computing and Information Systems
In certain database applications such as deductive databases, batch query processing, and recursive query processing etc., a single query can be transformed into a set ofclosely related database queries. Great benefits can be obtained by executing a group of related queries all together in a single unijied multi-plan instead of executing each query separately. In order to achieve this, Multiple Query Optimization (MQO) identifies common task(s) (e.g. common subezpressions, joins, etc.) among a set of query plans and creates a single unified plan (multiplan) which can be executed to obtain the required outputs forall queries at once. In this paper, …
Query Optimization And Processing In Federated Database Systems, Ee Peng Lim, Jaideep Srivastava
Query Optimization And Processing In Federated Database Systems, Ee Peng Lim, Jaideep Srivastava
Research Collection School Of Computing and Information Systems
No abstract provided.
Entity Identification In Database Integration: An Evidential Reasoning Approach, Ee Peng Lim, Jaideep Srivastava
Entity Identification In Database Integration: An Evidential Reasoning Approach, Ee Peng Lim, Jaideep Srivastava
Research Collection School Of Computing and Information Systems
Entity identification is the problem of matching object instances from different databases which correspond to the same real-world entity. In this paper, we present a 2-step entity identification process in which attributes for matching tuples may be missing in certain tuples, and thus need to be derived prior to the matching. To match tuples, we require identity rules which specify the conditions to be satisfied by a pair of tuples, from different databases, before they can be considered as modeling the same real-world entity. We also introduce ILFD's (instance-level functional dependencies) as a form of inference rules which derive the …
Memory-Adaptive External Sorting, Hwee Hwa Pang, Michael J. Carey, Miron Livny
Memory-Adaptive External Sorting, Hwee Hwa Pang, Michael J. Carey, Miron Livny
Research Collection School Of Computing and Information Systems
In real-time and goal-oriented database systems, the amount of memory assigned to queries that sort or join large relations may fluctuate due to contention from other higher priority transactions. This study focuses on techniques that enable external sorts both to reduce their buffer usage when they lose memory, and to effectively utilize any additional buffers that are given to them. We also show how these techniques can be extended to work with sort-merge joins. A series of experiments confirms that our proposed techniques are useful for sorting and joining large relations in the face of memory fluctuations.
Partially Preemptible Hash Joins, Hwee Hwa Pang, Michael J. Carey, Miron Livny
Partially Preemptible Hash Joins, Hwee Hwa Pang, Michael J. Carey, Miron Livny
Research Collection School Of Computing and Information Systems
With the advent of real-time and goal-oriented database systems, priority scheduling is likely to be an important feature in future database management systems. A consequence of priority scheduling is that a transaction may lose its buffers to higher-priority transactions, and may be given additional memory when transactions leave the system. Due to their heavy reliance on main memory, hash joins are especially vulnerable to fluctuations in memory availability. Previous studies have proposed modifications to the hash join algorithm to cope with these fluctuations, but the proposed algorithms have not been extensively evaluated or compared with each other. This paper contains …
Federated Autonomous Databases: Project Overview, Satya Prabhakar, Jiandong Huang, James Richardson, Jaideep Srivastava, Ee Peng Lim, Sham Navathe, Ashok Savarase, Mark Foresti
Federated Autonomous Databases: Project Overview, Satya Prabhakar, Jiandong Huang, James Richardson, Jaideep Srivastava, Ee Peng Lim, Sham Navathe, Ashok Savarase, Mark Foresti
Research Collection School Of Computing and Information Systems
The paper presents an overview of an ongoing research program, Federated Autonomous Databases, sponsored by Rome Laboratory (US Air Force) and conducted by Honeywell in collaboration with the University of Minnesota and Georgia Institute of Technology. This program is exploratory in nature and is aimed at understanding and solving, within the scope of the program definition, the problem of providing integrated access to distributed, heterogeneous and autonomous databases.
Entity Identification In Database Integration, Ee Peng Lim, Jaideep Srivastava, Satya Prabhakar, James Richardson
Entity Identification In Database Integration, Ee Peng Lim, Jaideep Srivastava, Satya Prabhakar, James Richardson
Research Collection School Of Computing and Information Systems
The objective of entity identification is to determine the correspondence between object instances from more than one database. Entity identification at the instance level, assuming that schema level heterogeneity has been resolved a priori, is examined. Soundness and completeness are defined as the desired properties of any entity identification technique. To achieve soundness, a set of identity and distinctness rules are established for entities in the integrated world. The use of extended key, which is the union of keys, and possibly other attributes, from the relations to be matched, and its corresponding identify rule are proposed to determine the equivalence …
Search For Τ-→Γμ-: A Test Of Lepton Number Conservation, A. Bean, M. Thulasidas
Search For Τ-→Γμ-: A Test Of Lepton Number Conservation, A. Bean, M. Thulasidas
Research Collection School Of Computing and Information Systems
A search for the lepton mumber violating decay of the τ lepton to the γμ final state has been performed with the CLEO II detector at the Cornell e+e− storage ring CESR. In a data sample that corresponds to an integrated luminosity of 1.55 fb−1, we observe no candidates in the signal region. We thus determine an upper limit of B(τ−→γμ−)
Tau Decays With One Charged Particle Plus Multiple Π0'S, M. Procario, Manoj Thulasidas
Tau Decays With One Charged Particle Plus Multiple Π0'S, M. Procario, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
With the CLEO-II detector at the Cornell Electron Storage Ring, we have measured branching fractions for tau lepton decay into one-prong final states with multiple π0’s B0hnπ, normalized to the branching fraction for tau decay into one charged particle and a single π0. We find B0h2π/B0hπ=0.345±0.006±0.016, B0h3π/B0hπ=0.041 ±0.003±0.005, and B0h4π/B0hπ=0.006±0.002±0.002.
Measurement Of Charmless Semileptonic Decays Of B Mesons, Bartelt; J.; Et Al., M. Thulasidas
Measurement Of Charmless Semileptonic Decays Of B Mesons, Bartelt; J.; Et Al., M. Thulasidas
Research Collection School Of Computing and Information Systems
No abstract provided.
Observation Of The Charmed Baryon C+ And Measurement Of The Isospin Mass Splittings Of The C, Crawford, G.; Et Al., M. Thulasidas
Observation Of The Charmed Baryon C+ And Measurement Of The Isospin Mass Splittings Of The C, Crawford, G.; Et Al., M. Thulasidas
Research Collection School Of Computing and Information Systems
No abstract provided.
Observation Of B0 Decay To Two Charmless Mesons, M. Battle, Manoj Thulasidas
Observation Of B0 Decay To Two Charmless Mesons, M. Battle, Manoj Thulasidas
Research Collection School Of Computing and Information Systems
We report results from a search for the decays B0→π+π-, B0→K+π-, and B0→K+K-. We find 90% confidence level upper limits on the branching fractions, Bππ
Evidence For Penguin-Diagram Decays: First Observation Of B→K*(892)Γ, R. Ammar, M. Thulasidas
Evidence For Penguin-Diagram Decays: First Observation Of B→K*(892)Γ, R. Ammar, M. Thulasidas
Research Collection School Of Computing and Information Systems
We have observed the decays B0→K*(892)0γ and B−→K*(892)−γ, which are evidence for the quark-level process b→sγ. The average branching fraction is (4.5±1.5±0.9)×10−5. This value is consistent with standard model predictions from electromagnetic penguin diagrams.
Study Of D0 Decays Into K̄0 And K̄*0, M. Procario, M. Thulasidas
Study Of D0 Decays Into K̄0 And K̄*0, M. Procario, M. Thulasidas
Research Collection School Of Computing and Information Systems
Using the CLEO II detector at CESR we have studied D0 decays into final states with a ¯K0 or ¯K*0, and have measured branching ratios for the decay modes D0→(¯K0¯K*0)π0, η, η′. These results are compared with predictions of various charm decay models, and contributions of final-state interactions are discussed.