bluuebunny/crossref_metadata_2025 huggingface dataset:
Report on the 19
th
Brazilian symposium on databases (SBBD 2004)
Authors: Lifschitz Sérgio , Laender Alberto H. F.
Published: November 2005

The Brazilian Symposium on Databases (SBBD) is an annual event promoted by the Brazilian Computer Society (SBC) through its Database Special Committee. In 2004, the 19
th
edition of SBBD was held in Brasília, Brazil's capital, on 18-20 October, organized by the Computer Science Department of the University of Brasília (UnB). As in the previous years, SBBD 2004 received the in-cooperation status from ACM SIGMOD and was partially supported by the VLDB Endowment, thus confirming the recognition of the international community of SBBD as the most important database event in Latin America.
Containment of aggregate queries
Authors: Cohen Sara
Published: November 2005

It is now common for databases to contain many gigabytes, or even many terabytes, of data. Scientific experiments in areas such as high energy physics produce data sets of enormous size, while in the business sector the emergence of decision-support systems and data warehouses has led organizations to build up gigantic collections of data. Aggregate queries allow one to retrieve concise information from such a database, since they can cover many data items while returning a small result. OLAP queries, used extensively in data warehousing, are based almost entirely on aggregation [4, 16]. Aggregate queries have also been studied in a variety of settings beyond relational databases, such as mobile computing [1], global information systems [21], stream data analysis [12], sensor networks [22] and constraint databases [2].
Databases in Virtual Organizations
Authors: Winslett Marianne
Published: November 2005

When the Databases in Virtual Organizations (DIVO) workshop convened after SIGMOD 2004 in Paris, many of us attending weren't sure what a virtual organization was, much less what relevance it could have to database research. Five hours later, as the lights snapped off in the rest of the building and the maintenance crew hovered patiently outside our meeting room, we had become a group with a mission: to let the database research community know what an incredible idea generator and testbed virtual organizations could be for research on information integration and data security.
Developments at ACM
TODS
Authors: Snodgrass Richard
Published: November 2005

The March 2005 issue of
TODS
has eight papers invited from the SIGMOD and PODS'2003 conferences. These papers are significantly extended versions of the conference papers, allowing the authors to refine and elaborate without the strictures of a twelve-page limit.
A framework for the assessment of operating systems for small computers
Authors: Saiedian Hossein , Siddiqi Munib
Published: November 2005

A number of high performance operating systems are now available for small computers on different hardware platforms. These operating systems offer many advanced features formerly reserved for their workstation and minicomputer counterparts. This article surveys the most widely used of such operating systems, namely OS/2, Windows NT, Linux and Macintosh System 7.5. It provides an account on the history, design objectives and evolution of these operating systems and discusses their key features, design concepts and implementation issues. An assessment and comparison of features, and capabilities is also provided. The assessment and comparison is based primarily on key features, such as memory management, multitasking capabilities, file system architecture, I/O support (such as asynchronous I/O, multimedia capabilities, plug and play devices, and on-demand load drivers), and networking capabilities (e.g., support for widely used protocols such as TCP/IP, SLIP/PPP, NetBIOS, NSF mounting, etc.).
From a technology graduate to a competent IT teacher
Authors: Lai Yiu-chi , Wong Tak-wah
Published: November 2005

Information Technology (IT) has become pervasive in our society and it is playing an increasingly important role in education. There is a growing expectation that teachers will be able to make effective use of IT in all facets of their work in schools. There are at least two major reasons which underpin the need to prepare IT teachers in secondary schools. First, schools are expected to prepare students for future jobs. It is quite clear that most of the jobs of the future will require some knowledge of IT. It is therefore important that students learn about IT while they are in schools. This indicates that there is a great need for more teachers who are competent in IT. In particular, secondary schools are short of teachers who are capable of teaching IT as a subject and to incorporate the current learning theories into practice. Second, given the increasing deployment and application of IT in secondary schools, there will be a serious shortage of teachers who are capable of managing and coordinating the use of IT across the school in the secondary context. Under these circumstances, we are offering the IT major in the Postgraduate Diploma in Education (Secondary) (PGDE(S)) Programme in our Institute. The IT Major is designed to prepare university graduates in technology discipline to be able to act as competent IT subject teachers for all levels in Hong Kong secondary schools. This article will discuss the rationale, principles and approach in designing the programme.
The Indiana Center for Database Systems at Purdue University
Authors: Ouzzani Mourad , Aref Walid G. , Bertino Elisa , Catlin Ann Christine , Clifton Christopher W. , Hon Wing-Kai , Elmagarmid Ahmed K. , Ghafoor Arif , Hambrusch Susanne E. , Prabhakar Sunil , Vitter Jeffrey S. , Zhang Xiang
Published: November 2005

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 diversity of its research topics, the large and diverse funding base, and the steady publication trend in top conferences and journals. ICDS was founded with an initial grant from the State of Indiana Corporation of Science and Technology in 1990. Since then it has grown to now have 9 faculty members and about 30 total researchers. This report describes the major research projects underway at ICDS as well as efforts to move research toward practice.
Report on the ninth conference on Software Engineering and Databases (JISBD 2004)
Authors: Hernández Juan , Pimentel Ernesto , Toval Ambrosio
Published: November 2005

The ninth edition of the Conference on Software Engineering and Databases (named JISBD after its initials in Spanish) was held in Málaga (Spain) November 10-12, 2004. This conference had its origins in two previous, separate events comprising two scientific communities closely related to the subjects of the conferences: on the one hand the Spanish Software Engineering Conference, held for the first time in Sevilla (Spain) in 1996, and, on the other, the Spanish Conference on Research and Education in Databases, held in A Coruña (Spain), also for the first time in the same year. These two events were joined in 1999, giving rise to the Fourth Conference on Software Engineering and Databases, for the first time with this name, which has been preserved to date.
Report on the 1st International Symposium on the Applications of Constraint Databases (CDB'04)
Authors: Kuijpers Bart , Revesz Peter
Published: November 2005

The 1st International Symposium on the Applications of Constraint Databases (CDB'04) was held on June 12-13, 2004, just before the ACM SIGMOD and PODS conferences, in the Amphithéatre de Chimie of the Université Pierre et Marie Curie in Paris, France. We acted as program committee chairs and Irène Guessarian and Patrick Cégielski as local organization chairs.
Simplifying construction of complex workflows for non-expert users of the Southern California Earthquake Center Community Modeling Environment
Authors: Maechling Philip , Chalupsky Hans , Dougherty Maureen , Deelman Ewa , Gil Yolanda , Gullapalli Sridhar , Gupta Vipin , Kesselman Carl , Kim Jihic , Mehta Gaurang , Mendenhall Brian , Russ Thomas , Singh Gurmeet , Spraragen Marc , Staples Garrick , Vahi Karan
Published: November 2005

Workflow systems often present the user with rich interfaces that express all the capabilities and complexities of the application programs and the computing environments that they support. However, non-expert users are better served with simple interfaces that abstract away system complexities and still enable them to construct and execute complex workflows. To explore this idea, we have created a set of tools and interfaces that simplify the construction of workflows. Implemented as part of the Community Modeling Environment developed by the Southern California Earthquake Center, these tools, are integrated into a comprehensive workflow system that supports both domain experts as well as non expert users.
A taxonomy of scientific workflow systems for grid computing
Authors: Yu Jia , Buyya Rajkumar
Published: November 2005

With the advent of Grid and application technologies, scientists and engineers are building more and more complex applications to manage and process large data sets, and execute scientific experiments on distributed resources. Such application scenarios require means for composing and executing complex workflows. Therefore, many efforts have been made towards the development of workflow management systems for Grid computing. In this paper, we propose a taxonomy that characterizes and classifies various approaches for building and executing workflows on Grids. The taxonomy not only highlights the design and engineering similarities and differences of state-of-the-art in Grid workflow systems, but also identifies the areas that need further research.
XML database support for distributed execution of data-intensive scientific workflows
Authors: Hastings Shannon , Ribeiro Matheus , Langella Stephen , Oster Scott , Catalyurek Umit , Pan Tony , Huang Kun , Ferreira Renato , Saltz Joel , Kurc Tahsin
Published: November 2005

In this paper we look at the application of XML data management support in scientific data analysis workflows. We describe a software infrastructure that aims to address issues associated with metadata management, data storage and management, and execution of data analysis workflows on distributed storage and compute platforms. This system couples a distributed, filter-stream based dataflow engine with a distributed XML-based data and metadata management system. We present experimental results from a biomedical image analysis use case that involves processing of digitized microscopy images for feature segmentation.
Database research at Bilkent University
Authors: Ulusoy Özgür
Published: November 2005

This report provides a brief description of the research activities of the Database Research Group of Bilkent University. The current research of the group is mainly focused on the topics of
Multimedia Databases
(in particular video database management and content-based retrieval of document images),
Web Databases
(in particular the modeling and querying of Web resources and focused crawling), and
Mobile Computing
(in particular moving object processing and mobile data management).
Data management research at the Middle East Technical University
Authors: Cicekli Nihan K. , Cosar Ahmet , Dogac Asuman , Polat Faruk , Senkul Pinar , Toroslu I. Hakki , Yazici Adnan
Published: November 2005

The Middle East Technical University (METU) (http://www.metu.edu.tr) is the leading technical university in Turkey. The department of Computer Engineering (http://www.ceng.metu.edu.tr) has twenty seven faculty members with PhDs, 550 undergraduate students and 165 graduate-students. The major research funding sources include the Scientific and Technical Research Council of Turkey (TÜBÍTAK), the European Commission, and the internal research funds of METU. Data management research conducted in the department is summarized in this article.
Query answering exploiting structural properties
Authors: Scarcello Francesco
Published: November 2005

We review the notion of hypertree width, a measure of the degree of cyclicity of hypergraphs that is useful for identifying and solving efficiently easy instances of hard problems, by exploiting their structural properties. Indeed, a number of relevant problems from different areas, such as database theory, artificial intelligence, and game theory, are tractable when their underlying hypergraphs have small (i.e., bounded by some fixed constant) hypertree width. In particular, we describe how this notion may be used for identifying tractable classes of database queries and answering such queries in an efficient way.
Some further analysis of the essential blocking recurrence
Authors: Robinson John T.
Published: November 2005

In previous work,
1
a random graph model of concurrency control was developed, in which there are
n
concurrent transactions (represented as vertices of a graph), and where for each pair of transactions (vertices), a conflict (edge between the vertices) initially occurs independently with probability
p
. Given such a graph, a
scheduling function
selects a subset of transactions to complete based on the conflicts and possibly on an ordering of the transactions. At the end of each unit of time, the transactions selected by the scheduling function to complete are removed from the graph, and are replaced by new transactions from a transaction sequence. For each pair of transactions in the new graph, if the transactions were both in the previous graph then a conflict occurs between them if and only if there was a conflict in the previous graph; otherwise one or both of the transactions are new and a conflict occurs independently with probability
p
.
Minimal covers revisited
Authors: Diederich Jim
Published: November 2005

In [1] Nummenmaa and Tanisch show that the algorithm in [2] for computing minimal covers is incorrect even though it purports to correct the algorithms in [3-6]. As they illustrate with F = { A B → C}, the algorithm in [2] allows B to be eliminated as an extraneous attribute since the dependency AB → C is implied by A → C using augmentation. Thus F is replaced by F′ = [A → C], which is clearly not equivalent to F. The problematic step of the algorithm in [2] that allows this to occur is Consider each dependency X → A in some order. If Z is a subset of X such that F is contained in the closure of (F - {X → A}) ∪ {Z → A], then immediately replace X → A by Z → A in F. This step continues until no left side of any dependency in F can be reduced
Accommodating imprecision in database systems
Authors: Motro Amihai
Published: November 2005

Most database systems are designed under assumptions of precision of both the data stored in their databases, and the requests to retrieve data. In reality, however, these assumptions are often invalid, and in recent years considerable attention has been given to issues of imprecision in database systems. In this paper we review the major solutions for accommodating imprecision, and we describe issues that have yet to addressed, offering possible research directions.
Spatial database access methods
Authors: Salzberg Betty , Lomet David B.
Published: November 2005

In the discussion of research issues in spatial databases (SIGMOD Record vol. 19, no. 4, Dec 1990) we stated the need for a robust framework for analytical comparison of a broad range of spatial access methods. The utility of such a comparison, even of very closely related access methods, was shown in [FALO87]. A necessary precondition for a meaningful analytical comparison is the existence of strong analytical results for individual access methods. In the following paper, Salzberg and Lomet take the worst case analytical results on fan-out and average storage utilization they obtained for their hB-tree [LOME89,LOME90] and extend the analysis to another robust method, Z-order encoding [OREN84]. We think this paper is a start on the comparative assessment of access methods based on analytical results. We hope to see future work extend the framework beyond worst case analysis, and to other access methods as well.
Technique for universal quantification in SQL
Authors: Fratarcangeli Claudio
Published: November 2005

Universal quantification is expressed in ANSI SQL with negated existential quantification because there is no direct support for universal quantification in ANSI SQL. However, the lack of explicit support for universal quantification diminishes the userfriendliness of the language because some queries are expressed more naturally using universal quantification than they are using negated existential quantification. It is the intent of this paper to describe a technique to facilitate the construction of universal quantification queries in ANSI SQL. The technique is based upon a proposed extension to ANSI SQL to incorporate explicit general support for universal quantification.
A more general model for handling missing information in relational databases using a 3-valued logic
Authors: Yue Kwok-bun
Published: November 2005

Codd proposed the use of two interpretations of nulls to handle missing information in relational databases that may lead to a 4-valued logic [Codd86, Codd87]. In a more general model, three interpretations of nulls are necessary [Roth, Zani]. Without simplification, this may lead to a 7-valued logic, which is too complicated to be adopted in relational databases. For such a model, there is no satisfactory simplification to a 4-valued logic. However, by making a straightforward simplification and using some proposed logical functions, a 3-valued logic can handle all three interpretations.
Modern client-server DBMS architectures
Authors: Roussopoulos Nick , Delis Alexis
Published: November 2005

In this paper, we describe three Client-Server DBMS architectures. We discuss their functional components and provide an overview of their performance characteristics.
Building reusable data representations with FaceKit
Authors: King Roger , Novak Michael
Published: November 2005

FaceKit is a toolkit for designing interfaces to object-oriented databases. It provides users with a set of tools for building custom interfaces with minimal programming. This is accomplished by combining techniques from the realm of User Interface Management Systems (UIMS) with a built-in knowledge about the specific kinds of techniques used by object-oriented databases. One of the main features of FaceKit is the ability to rapidly create reusable graphical constructs for representing schema or data objects. These constructs are stored within the database as methods, often dependent on attribute data. Building up a library of these data representations facilities reusability within a variety of databases.
EUG'91 meeting notes
Authors: Wilson Peter R.
Published: November 2005

The first annual meeting of the EXPRESS Users Group was held in Houston, Texas on 17-18 October 1991. There was a good international audience at the conference, two thirds of whom were from North America with the remainder from several European countries and Japan.
Summary of database research activities at the University of Massachusetts, Amherst
Authors: Ramamritham K. , Moss E. , Stankovic J. A. , Stemple D. , Croft B. , Towsley D.
Published: November 2005

At the University of Massachusetts, we have been conducting research in the following database related areas: theoretical support for database system development, database programming languages, flexible concurrency control and transaction management, real-time databases, and information retrieval. The following is a summary of our research in each area.
A process-oriented scientific database model
Authors: Pratt J. Michael , Cohen Maxine
Published: November 2005

A database model is proposed for organizing data that describes natural processes studied experimentally. Adapting concepts from object-oriented and temporal databases, this process-oriented scientific database model (POSDBM) identifies two data object types (independent and dependent variables) and two types of relationships (becomes-a and affects-a) between data objects. Successive versions of dependent variable objects are associated by the becomes-a relationship, while independent and dependent variable objects are associated by the affects-a relationship. Thus, a process can be viewed as a sequence of states (versions) of a dependent variable object whose attributes are affected over time by independent variable objects.
Interoperability and object identity
Authors: Eliassen Frank , Karlsen Randi
Published: November 2005

Data model transparency can be achieved by providing a canonical language format for the definition and seamless manipulation of multiple autonomous information bases. In this paper we assume a canonical data and computational model combining the function and object-oriented paradigms.

We investigate the concept of identity as a property of an object and the various ways this property is supported in existing databases, in relation to the object-oriented canonical data model.

The canonical data model is the tool for combining and integrating preexisting syntactical homogeneous, but semantical heterogeneous data types into generalized unifying data types. We identify requirements for object identity in federated systems, and discuss problems of object identity and semantical object replication arising from this new abstraction level. We argue that a strong notion of identity at the federated level can only be acheived by weakening strict autonomy requirements of the component information bases. Finally we discuss various solutions to this problem that differ in their requirements with repect to giving up autonomy.
Suitability of datamodels as canonical models for federated databases
Authors: Saltor F. , Castellanos M. , García-Solaco M.
Published: November 2005

We develop a framework of characteristics, essential and recommended, that a data model should have to be suitable as canonical model for federated databases. This framework is based on the two factors of the representation ability of a model:
expressiveness
and
semantic relativism
.

Several data models are analyzed with repect to the characteristics of the framework, to evaluate their adequacy as canonical models.
Data/knowledge packets as a means of supporting semantic heterogeneity in multidatabase systems
Authors: Weishar Doyle , Kerschberg Larry
Published: November 2005

Semantic heterogeneiry in heterogeneous autonomous databases poses problems in instance matches, units conversion (value interpretation), contextual and structural mismatches, etc. In this work we examine some of the research issues in semantic heterogeniety and propose a novel architecture for resolving such problems. The approach involves the use of Artifical Intelligence tools and techniques to construct “domain models,” that is data and knowledge representations of the constituent databases and an overall domain model of the semantic interactions among the databases. These domain models are represented as knowledge sources (KSs) in a blackboard architecture. This architecture lends itself to an opportunistic approach to query processing and goal-directed problem solving. We introduce the notion of Data/Knowledge Packets as a means of supporting both operational and structural semantic heterogeneity.
The metadatabase project at Rensselaer
Authors: Hsu Cheng
Published: November 2005

The Metadatabase project is a multi-year research effort at Rensselaer Polytechnic Institute. Sponsored by industry (ALCOA, DEC, GE, CM, IBM and other) through Rensselaer's Computer Integrated Manufacturing Program, this project seeks to develop novel concepts, methods and techniques for achieving information integration across major functional systems pertaining to computerized manufacturing enterprises. Thus, the metadatabase model emcompasses the generic tasks of heterogeneous, distributed, aand autonomous databases administration, but also includes information resources management and integration of concurrent (functional) systems. The model entails (1) an integrated data and knowledge modeling and representation method; (2) an online kernel (the metadatabase) for information modeling and management; (3) metadatabase assisted global query formulation and processing; (4) a concurrent architectural whereby global synergies are achieved through (distributed) metadata management rather than synchronization of (distributed) database processing; and (5) a theory of information requirements for integration. A metadatabase prototype was recently demonstrated to the industrial sponsors. The basic concept of the metadatabase model is discussed in this paper.
Extensible/rule based query rewrite optimization in Starburst
Authors: Pirahesh Hamid , Hellerstein Joseph M. , Hasan Waqar
Published: November 2005

This paper describes the Query Rewrite facility of the Starburst extensible database system, a novel phase of query optimization. We present a suite of rewrite rules used in Starburst to transform queries into equivalent queries for faster execution, and also describe the production rule engine which is used by Starburst to choose and execute these rules. Examples are provided demonstrating that these Query Rewrite transformations lead to query execution time improvements of orders of magnitude, suggesting that Query Rewrite in general—and these rewrite rules in particular—are an essential step in query optimization for modern database systems.
Event specification in an active object-oriented database
Authors: Gehani N. H. , Jagadish H. V. , Shmueli O.
Published: November 2005

The concept of a trigger is central to any active database. Upon the occurrence of a trigger event, the trigger is “fired”, i.e, the trigger action is executed. We describe a model and a language for specifying basic and composite trigger events in the context of an object-oriented database. The specified events can be detected efficiently using finite automata.

We integrate our model with O++, the database programming language for the ode object database being developed at AT&T Bell Labs. We propose a new Event-Action model, which folds into the event specification the condition part of the well-known Event-Condition-Action model and avoids the multiple coupling modes between the event, condition, and action trigger components.
PARDES
Authors: Etzion Opher
Published: November 2005

Most active database models adopted an
event-driven
approach in which whenever a given event occurs the database triggers some actions. Many derivations are
data-driven
by nature, deriving the values of data-elements as a function of the values of other derived data-elements. The handling of such rules by current active databases suffers from semantic and pragmatic fallacies. This paper explores these fallacies and reports about the PARDES language and supporting architecture, aiming at the support of
data-driven
rules, in an active database framework.
SIRIO
Authors: Costilla C. R. , Bas M. J. , Villamor J.
Published: November 2005

This paper presents the SIRIO project, a commercial experience within Spanish industry, developed for Tecnatom S.A. by the Data and Knowledge Bases Research Group at the Technical University of Madrid. SIRIO runs over a heterogeneous local area network, with a
client-server
architecture, using the following tools: Oracle as RDBMS, running over a Unix server, TCP/IP as a communication protocol, Ethernet TOOLKIT for the distributed
client-server
architecture, and C as the host programming language for the distributed applications (every one of them is rather complex and very different from the rest). The system uses computers with MS-DOS, connected to the server over the LAN.

SIRIO is mainly based on the conceptual design of an Rdb, upon which several distributed applications are operational as big software modules. These applications are: 1.- The inspection programs, the management of their corresponding criteria and the automatic generation of queries. 2.- Graphics processing and interface definition. 3.- Interactive Rdb updating. 4.- Historical db management. 5.- Massive load of on-field obtained data. 6.- Report and query application.

The approach of the SIRIO integrated information system presented here is a pioneering one. There are about two dozen companies worldwide in this field and none has developed such an advanced system to this day. From 1992, SIRIO is totally operational in the Tecnatom S.A. industry. It constitutes an important tool to obtain the reports (from different plants) for the clients, for the State control organizations, and for the specialized analyst staff.
Bibliography on spatiotemporal databases
Authors: Al-Taha Khaled K. , Snodgrass Richard Thomas , Soo Michael D.
Published: November 2005

Spatial and temporal databases are important and well-established sub-disciplines of database research. Some 350 papers in temporal databases have appeared, authored by almost 300 researchers. The literature on spatial databases is also substantial; the bibliography of Samet's landmark book on spatial data structures lists 823 references.
Extending the scope of database services
Authors: Barbará Daniel
Published: November 2005

A wide variety of important data remains outside of the scope of database management systems. In recent years researchers have been making efforts in two directions: first, developing database management systems that can support non-traditional data, and secondly, offering database services for data that remains under control of autonomous (not necessarily database) systems. The purpose of this paper is to provide a brief review of these efforts.
An event/trigger mechanism to enforce complex consistency constraints in design databases
Authors: Dittrich Klaus R. , Kotz Angelika M. , Mülle Jutta A.
Published: November 2005

Data objects in engineering applications, especially computer aided design, show highly complex structures and a lot of intricate dependencies. Hence a large amount of variably composed consistency constraints have to be dealt with. Furthermore, long transactions which are typical for CAD result in the need to tolerate inconsistencies over unpredictably long periods of time. The demands on mechanisms to enforce consistency in design database systems thus differ from those in business and administrative applications. Comprehensive consistency of the design data can only be attained by degrees. The time and extent of checking have to be determined dynamically and under control by the user. In the case of consistency violations, flexible kinds of reaction are necessary. In this paper we propose an event/trigger mechanism to enforce consistency in design databases that complements the transaction-oriented mechanisms suitable for traditional applications. The underlying ideas are derived from exception handling in programming languages. We present in detail the requirements to meet and how our concept copes with them. We also present an implementation that provides reasonable performance.
Merging application-centric and data-centric approaches to support transaction-oriented multi-system workflows
Authors: Breitbart Y. , Deacon A. , Schek H.-J. , Sheth A. , Weikum G.
Published: November 2005

Workflow management is primarily concerned with dependencies between the tasks of a workflow, to ensure correct control flow and data flow. Transaction management, on the other hand, is concerned with preserving data dependencies by preventing execution of conflicting operations from multiple, concurrently executing tasks or transactions. In this paper we argue that many applications will be served better if the properties of transaction and workflow models are supported by an integrated architecture. We also present preliminary ideas towards such an architecture.
NSF and HPCC under attack
Authors: Winslett Marianne
Published: November 2005

In this issue we describe recent turmoil over NSF, ARPA, and HPCC, and cover funding opportunities from NSF, CRA, NIH, the Army, the Air Force, NIST, and NASA.
A snapshot differential refresh algorithm
Authors: Lindsay Bruce , Haas Laura , Mohan C. , Pirahesh Hamid , Wilms Paul
Published: November 2005

This article presents an algorithm to refresh the contents of database snapshots. A database
snapshot
is a read-only table whose contents are extracted from other tables in the database. The snapshot contents can be periodically
refreshed
to reflect the current state of the database. Snapshots are useful in many applications as a cost effective substitute for replicated data in a distributed database system.

When the snapshot contents are a simple restriction and projection of a single base table,
differential
refresh techniques can reduce the message and update costs of the snapshot refresh operation. The algorithm presented annotates the base table to detect the changes which must be applied to the snapshot table during snapshot refresh. The cost of maintaining the base table annotations is minimal and the amount of data transmitted during snapshot refresh is close to optimal in most circumstances.
Constructing queries from tokens
Authors: Motro Amihai
Published: November 2005

A database token is a value of either the data or the metadata. Usually, such tokens are combined with formal language constructs to form queries. In this paper we show how a given set of tokens may be completed to a proper query. This process provides a useful means of communication between naive users and databases, allowing them to express simple requests by listing several tokens. As the inferred query is always shown to the user, this process has a side effect of instructing the user in the proper use of the query language. The method is described and demonstrated with relational databases, but its principles may be implemented with other databases as well.
The SEQUOIA 2000 storage benchmark
Authors: Stonebraker Michael , Frew Jim , Gardels Kenn , Meredith Jeff
Published: November 2005

This paper presents a benchmark that concisely captures the data base requirements of a collection of Earth Scientists working in the SEQUOIA 2000 project on various aspects of global change research. This benchmark has the novel characteristic that it uses real data sets and real queries that are representative of Earth Science tasks. Because it appears that Earth Science problems are typical of the problems of engineering and scientific DBMS users, we claim that this benchmark represents the needs of this more general community. Also included in the paper are benchmark results for three example DBMSs: GRASS, IPW and POSTGRES.
Implementation of the CORAL deductive database system
Authors: Ramakrishnan Raghu , Srivastava Divesh , Sudarshan S. , Seshadri Praveen
Published: November 2005

CORAL is a deductive database system that supports a rich declarative language, provides a wide range of evaluation methods, and allows a combination of declarative and imperative programming. The data can be persistent on disk or can reside in main-memory. We describe the architecture and implementation of CORAL.

There were two important goals in the design of the CORAL architecture: (1) to integrate the different evaluation strategies in a reasonable fashion, and (2) to allow users to influence the optimization techniques used so as to exploit the full power of the CORAL implementation. A CORAL declarative program can be organized as a collection of interacting modules and this modular structure is the key to satisfying both these goals. The high level module interface allows modules with different evaluation techniques to interact in a transparent fashion. Further, users can optionally tailor the execution of a program by selecting from among a wide range of control choices at the level of each module.

CORAL also has an interface with C++, and users can program in a combination of declarative CORAL, and C++ extended with CORAL primitives. A high degree of
extensibility
is provided by allowing C++ programmers to use the class structure of C++ to enhance the CORAL implementation.
Atomic incremental garbage collection and recovery for a large stable heap
Authors: Kolodner Elliot K. , Weihl William E.
Published: November 2005

A
stable heap
is storage that is managed automatically using garbage collection, manipulated using atomic transactions, and accessed using a uniform storage model. These features enhance reliability and simplify programming by preventing errors due to explicit deallocation, by masking failures and concurrency using transactions, and by eliminating the distinction between accessing temporary storage and permanent storage. Stable heap management is useful for programming languages for reliable distributed computing, programming languages with persistent storage, and object-oriented database systems.

Many applications that could benefit from a stable heap (e.g., computer-aided design, computer-aided software engineering, and office information systems) require large amounts of storage, timely responses for transactions, and high availability. We present garbage collection and recovery algorithms for a stable heap implementation that meet these goals and are appropriate for stock hardware. The collector is incremental: it does not attempt to collect the whole heap at once. The collector is also atomic: it is coordinated with the recovery system to prevent problems when it moves and modifies objects. The time for recovery is independent of heap size, even if a failure occurs during garbage collection.
Mining association rules between sets of items in large databases
Authors: Agrawal Rakesh , Imieliński Tomasz , Swami Arun
Published: November 2005

We are given a large database of customer transactions. Each transaction consists of items purchased by a customer in a visit. We present an efficient algorithm that generates all significant association rules between items in the database. The algorithm incorporates buffer management and novel estimation and pruning techniques. We also present results of applying this algorithm to sales data obtained from a large retailing company, which shows the effectiveness of the algorithm.
Efficient processing of spatial joins using R-trees
Authors: Brinkhoff Thomas , Kriegel Hans-Peter , Seeger Bernhard
Published: November 2005

Spatial joins are one of the most important operations for combining spatial objects of several relations. The efficient processing of a spatial join is extremely important since its execution time is superlinear in the number of spatial objects of the participating relations, and this number of objects may be very high. In this paper, we present a first detailed study of spatial join processing using R-trees, particularly R*-trees. R-trees are very suitable for supporting spatial queries and the R*-tree is one of the most efficient members of the R-tree family. Starting from a straightforward approach, we present several techniques for improving its execution time with respect to both, CPU- and I/O-time. Eventually, we end up with an algorithm whose total execution time is improved over the first approach by an order of magnitude. Using a buffer of reasonable size, I/O-time is almost optimal, i.e. it almost corresponds to the time for reading each required page of the relations exactly once. The performance of the various approaches is investigated in an experimental performance comparison where several large data sets from real applications are used.
Evaluation of signature files as set access facilities in OODBs
Authors: Ishikawa Yoshiharu , Kitagawa Hiroyuki , Ohbo Nobuo
Published: November 2005

Object-oriented database systems (OODBs) need efficient support for manipulation of complex objects. In particular, support of queries involving evaluations of set predicates is often required in handling complex objects. In this paper, we propose a scheme to apply signature file techniques, which were originally invented for text retrieval, to the support of set value accesses, and quantitatively evaluate their potential capabilities. Two signature file organizations, the sequential signature file and the bit-sliced signature file, are considered and their performance is compared with that of the nested index for queries involving the set inclusion operator (
⊆
). We develop a detailed cost model and present analytical results clarifying their retrieval, storage, and update costs. Our analysis shows that the bit-sliced signature file is a very promising set access facility in OODBs.
What to teach about databases
Authors: Motro Amihai
Published: November 2005

Lately, there has been increased pressure on universities to place more emphasis on teaching, relative to research. Hence, this is a good time to discuss the state of database instruction in universities. The annual SIGMOD Conference brings together both the “producers” and the “consumers” of database education (i.e., university professors, and professionals representing research and development organizations). Hence, this is a good place to hold such a discussion.
Modularity and tuning mechanisms in the O2 System
Authors: Vélez Fernando
Published: November 2005

The O
2
System is a commercial Object-Oriented Database Management System with a complete development environment and a set of user interface tools. In this presentation, we focus on the modularity and application tuning facilities of the system.
IBM's relational DBMS products
Authors: Mohan C.
Published: November 2005

This paper very briefly summarizes the features and technologies implemented in the IBM relational DBMS products. The topics covered include record and index management, concurrency control and recovery methods, commit protocols, query optimization and execution techniques, high availability and support for parallelism and distributed data. Some indications of likely future product directions are also given.
Parallel database processing on the KSR1 computer
Authors: Tseng Emy , Reiner David
Published: November 2005

The Kendall Square Research high performance computer (KSR1) provides a spectrum of parallel database processing techniques to achieve scalability and performance in a shared memory environment. The techniques include running multiple transactions in parallel, decomposing queries into parallel subqueries, running multiple instances of the DBMS and partitioning data over disks. These techniques enable on-line transactions to be run in parallel at high throughput rates and decision-support queries to be parallelized and executed very rapidly.

This paper focuses upon two of the parallel database processing techniques used on the KSR1—the Kendall Square Query Decomposer and the Oracle Parallel Server. The Query Decomposer intercepts costly decision support queries and decomposes them into subqueries which are executed in parallel. Parallel Server enables multiple ORACLE instances to run simultaneously on the same database.
Issues and approaches for migration/cohabitation between legacy and new systems
Authors: Nassif Rodolphe , Mitchusson Don
Published: November 2005

Corporate Subject Data Bases (CSDB) are being introduced to reduce data redundancy, maintain the integrity of the data, provide a uniform data access interface, and have data readily available to make business decisions. During the transition phase, there is a need to maintain Legacy Systems (LS), CSDB, and to synchronize between them. Choosing the right granularity for migration of data and functionality is essential to the success of the migration strategy. Technologies being used to support the transition to CSDB include relational systems supporting stored procedures, remote procedures, expert systems, object-oriented approach, reengineering tools, and data transition tools. For our Customer CSDB to be deployed in 1993, cleanup of data occurs during initial load of the CSDB. Nightly updates are needed during the transition phase to account for operations executed through LS. There is a lack of an integrated set of tools to help in the transition phase.
The international directory network and connected data information systems for research in the earth and space sciences
Authors: Thieman James R.
Published: November 2005

Many researchers are becoming aware of the International Directory Network (IDN), an interconnected federation of international directories to Earth and space science data. These directories may become distributed nodes of a single, virtual master data directory of the future. Not as many are aware, however, of the many Earth-and-space-sciece-relevant information systems which can be accessed automatically from the directories. After determining potentially useful data sets in various disciplines through IDN directories it is becoming increasingly possible to get detailed information about the correlative possibilities of these data sets through the connected guide/catalog and inventory systems. Such capabilities as data set browse, subsetting, analysis, etc. are available now and will be improving in the future.
Multidatabase interdependencies in industry
Authors: Sheth Amit P. , Karabatis George
Published: November 2005

In this paper we address the problem of data consistency between interrelated data. In industrial environments, lack of consistent data creates difficulties in interoperation between systems and often requires manual interventions to restart operations that fail due to inconsistent data. We report the results of a study to understand applicability, adequacy and advantages of a framework we had proposed earlier to specify interdatabase dependencies in multidatabase environments. We studied several existing Bellcore systems and identified examples of interdependent data. The examples demonstrate that the framework allows precise and detailed specification of complex interdependencies that lead to efficient strategies to enforce the consistency requirements among the corporate data managed in multiple databases. We believe that our specification framework can help in the maintenance of data that meet a business's consistency needs, reduce time consuming and costly manual operations, and provide data of better quality to end users.
The design and implementation of CoBase
Authors: Chu Wesley W. , Merzbacher Matthew , Berkovich Ladislav
Published: November 2005

CoBase, a cooperative database, is a new type of distributed database that integrates knowledge base technology with database systems to provide cooperative (approximate and conceptual) query answering. Based on the database schema and application characteristics, data are organized into conceptual (type abstraction) hierarchies. The higher levels of the hierarchy provide a more abstract data representation than the lower levels. Generalization (moving up in the hierarchy), specialization (moving down in the hierarchy) and association (moving between hierarchies) are the three key operations in deriving cooperative query answers.

Relaxation in CoBase can also be specified explicitly in the query by the user or calling program through cooperative operators. We have extended SQL to CSQL by adding cooperative primitives. We describe the CoBase software implementation, including an inter-module data protocol that provides a uniform module interface. This modular approach provides flexibility in adding new relaxation modules and simplifies software maintenance.

CoBase uses LOOM as its knowledge representation and inference system and supports relational data bases (e.g. Oracle and Sybase). We have demonstrated the feasibility and functionality of CoBase on top of a Transportation Database. The CoBase methodology has also been adopted in the multi-media medical distributed database project at UCLA, which provides approximate query answers to medical queries.
The LOGRES prototype
Authors: Cacace F. , Ceri S. , Crespi-Reghizzi S. , Fraternali P. , Paraboschi S. , Tanca L.
Published: November 2005

Logres is a new-generation database system integrating features from deductive and object-oriented databases [1, 2, 3, 4, 5]. The data model of Logres supports structural and semantic complexity through a rich collection of concepts from object-oriented models. The rule language allows for the manipulation of complex objects, the generation of new objects, and the definition of passive and active constraints. The application of set of rules to database states is controlled by means of qualifiers, which dictate the side effects of rules; qualifiers are the unique procedural feature of Logres, otherwise a fully declarative language.