bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring XML data on the Web
Authors: Nguyen Benjamin , Abiteboul Serge , Cobena Grégory , Preda Mihaí
Published: November 2005

We consider the monitoring of a flow of incoming documents. More precisely, we present here the monitoring used in a very large warehouse built from XML documents found on the web. The flow of documents consists in XML pages (that are warehoused) and HTML pages (that are not). Our contributions are the following:

a subscription language which specifies the monitoring of pages when fetched, the periodical evaluation of continuous queries and the production of XML reports.

the description of the architecture of the system we implemented that makes it possible to monitor a flow of millions of pages per day with millions of subscriptions on a single PC, and scales up by using more machines.

a new algorithm for processing alerts that can be used in a wider context.

We support monitoring at the page level (e.g., discovery of a new page within a certain semantic domain) as well as at the element level (e.g., insertion of a new electronic product in a catalog).

This work is part of the Xyleme system. Xyleme is developed on a cluster of PCs under Linux with Corba communications. The part of the system described in this paper has been implemented. We mention first experiments.
Applying the golden rule of sampling for query estimation
Authors: Wu Yi-Leh , Agrawal Divyakant , El Abbadi Amr
Published: November 2005

Query size estimation is crucial for many database system components. In particular, query optimizers need efficient and accurate query size estimation when deciding among alternative query plans. In this paper we propose a novel sampling technique based on the golden rule of sampling, introduced by von Neumann in 1947, for estimating range queries. The proposed technique randomly samples the frequency domain using the cumulative frequency distribution and yields good estimates without any a priori knowledge of the actual underlying distribution of spatial objects. We show experimentally that the proposed sampling technique gives smaller approximation error than the Min-Skew histogram based and wavelet based approaches for both synthetic and real datasets. Moreover, the proposed technique can be easily extended for higher dimensional datasets.
Data-driven understanding and refinement of schema mappings
Authors: Yan Ling Ling , Miller Renée J. , Haas Laura M. , Fagin Ronald
Published: November 2005

At the heart of many data-intensive applications is the problem of quickly and accurately transforming data into a new form. Database researchers have long advocated the use of declarative queries for this process. Yet tools for creating, managing and understanding the complex queries necessary for data transformation are still too primitive to permit widespread adoption of this approach. We present a new framework that uses data examples as the basis for understanding and refining declarative schema mappings. We identify a small set of intuitive operators for manipulating examples. These operators permit a user to follow and refine an example by walking through a data source. We show that our operators are powerful enough both to identify a large class of schema mappings and to distinguish effectively between alternative schema mappings. These operators permit a user to quickly and intuitively build and refine complex data transformation queries that map one data source into another.
Reconciling schemas of disparate data sources
Authors: Doan AnHai , Domingos Pedro , Halevy Alon Y.
Published: November 2005

A data-integration system provides access to a multitude of data sources through a single mediated schema. A key bottleneck in building such systems has been the laborious manual construction of semantic mappings between the source schemas and the mediated schema. We describe LSD, a system that employs and extends current machine-learning techniques to semi-automatically find such mappings. LSD first asks the user to provide the semantic mappings for a small set of data sources, then uses these mappings together with the sources to train a set of learners. Each learner exploits a different type of information either in the source schemas or in their data. Once the learners have been trained, LSD finds semantic mappings for a new data source by applying the learners, then combining their predictions using a meta-learner. To further improve matching accuracy, we extend machine learning techniques so that LSD can incorporate domain constraints as an additional source of knowledge, and develop a novel learner that utilizes the structural information in XML documents. Our approach thus is distinguished in that it incorporates multiple types of knowledge. Importantly, its architecture is extensible to additional learners that may exploit new kinds of information. We describe a set of experiments on several real-world domains, and show that LSD proposes semantic mappings with a high degree of accuracy.
Enabling dynamic content caching for database-driven web sites
Authors: Candan K. Selçuk , Li Wen-Syan , Luo Qiong , Hsiung Wang-Pin , Agrawal Divyakant
Published: November 2005

Web performance is a key differentiation among content providers. Snafus and slowdowns at major web sites demonstrate the difficulty that companies face trying to scale to a large amount of web traffic. One solution to this problem is to store web content at server-side and edge-caches for fast delivery to the end users. However, for many e-commerce sites, web pages are created dynamically based on the current state of business processes, represented in application servers and
databases
. Since application servers, databases, web servers, and caches are independent components, there is no efficient mechanism to make changes in the database content reflected to the cached web pages. As a result, most application servers have to mark dynamically generated web pages as non-cacheable. In this paper, we describe the architectural framework of the CachePortal system for enabling dynamic content caching for database-driven e-commerce sites. We describe techniques for intelligently invalidating dynamically generated web pages in the caches, thereby enabling
caching
of web pages generated based on database contents. We use some of the most popular components in the industry to illustrate the deployment and applicability of the proposed architecture.
Content integration for e-business
Authors: Stonebraker Michael , Hellerstein Joseph M.
Published: November 2005

We define the problem of content integration for E-Business, and show how it differs in fundamental ways from traditional issues surrounding data integration, application integration, data warehousing and OLTP. Content integration includes catalog integration as a special case, but encompasses a broader set of applications and challenges. We explore the characteristics of content integration and required services for any solution. In addition, we explore architectural alternatives and discuss the use of XML in this arena.
Experiences in mining aviation safety data
Authors: Nazeri Zohreh , Bloedorn Eric , Ostwald Paul
Published: November 2005

The goal of data analysis in aviation safety is simple: improve safety. However, the path to this goal is hard to identify. What data mining methods are most applicable to this task? What data are available and how should they be analyzed? How do we focus on the most interesting results? Our answers to these questions are based on a recent research project we completed. The encouraging news is that we found a number of aviation safety offices doing commendable work to collect and analyze safety-related data. But we also found a number of areas where data mining techniques could provide new tools that either perform analyses that were not considered before, or that can now be done more easily.

Currently, Aviation Safety offices collect and analyze the incident reports by a combination of manual and automated methods. Data analysis is done by safety officers who are well familiar with the domain, but not with data mining methods. Some Aviation Safety officers have tools to automate the database query and report generation process. However, the actual analysis is done by the officer with only fairly rudimentary tools to help extract the useful information from the data.

Our research project looked at the application of data mining techniques to aviation safety data to help Aviation Safety officers with their analysis task. This effort led to the creation of a tool called the “Aviation Safety Data Mining Workbench”. This paper describes the research effort, the workbench, the experience with data mining of Aviation Safety data, and lessons learned.
Data management
Authors: Meseck Reed M.
Published: November 2005

This paper describes some of the ways the Internet and World Wide Web have affected databases and data warehousing and the lasting impact in these areas.
Fast-Start
Authors: Lahiri Tirthankar , Ganesh Amit , Weiss Ron , Joshi Ashok
Published: November 2005

Availability requirements for database systems are more stringent than ever before with the widespread use of databases as the foundation for ebusiness. This paper highlights
Fast-Start
™
Fault Recovery
, an important availability feature in Oracle, designed to expedite recovery from unplanned outages. Fast-Start allows the administrator to configure a running system to impose predictable bounds on the time required for crash recovery. For instance, fast-start allows fine-grained control over the duration of the roll-forward phase of crash recovery by adaptively varying the rate of checkpointing with minimal impact on online performance. Persistent transaction locking in Oracle allows normal online processing to be resumed while the rollback phase of recovery is still in progress, and fast-start allows quick and transparent rollback of changes made by uncommitted transactions prior to a crash.
PBIR - perception-based image retrieval
Authors: Chang Edward , Cheng Kwang-Ting , Chang Lihyuarn L.
Published: November 2005

We demonstrate a system that we have built on our proposed perception-based image retrieval (PBIR) paradigm. This PBIR system achieves accurate similarity measurements by rooting image characterization in human perception and by learning user's query concept through an intelligent sampling process. We show that our system can usually grasp a user's query concept with a small number of labeled instances.
Semantic B2B integration
Authors: Bussler Christoph
Published: November 2005

The tutorial “Semantic B2B Integration” will give an introduction to the field of business-to-business (B2B) integration from a technical viewpoint with the focus on semantic integration aspects. The set of B2B integration concepts is introduced as well as their implementation in form of a technical semantic B2B integration architecture. A mix of examples is taken illustrating the problems that need to be solved in semantic B2B integration projects. The tutorial enables the audience to identify semantic B2B integration problems as well as to determine the benefits and deficiencies of various technical integration architecture approaches or B2B integration technologies.
Integrating temporal, real-time, an active databases
Authors: Ramamritham Krithi , Sivasankaran Raju , Stankovic John A. , Towsley Don T. , Xiong Ming
Published: November 2005

To meet the needs of many real-world control applications, concepts from Temporal, Real-Time, and Active Databases must be integrated:

Since the system's data is supposed to reflect the environment being controlled, they must be updated frequently to maintain temporal validity;

Many activities, including those that perform the updates, work under time constraints;

The occurrence of events, for example, emergency events, trigger actions.

In these systems, meeting
timeliness
,
predictability
, and
QoS guarantee
requirements — through appropriate resource and overload management — become very important. So, algorithms and protocols for concurrency control, recovery, and scheduling are needed. These algorithms must exploit semantics of the
data
and the
transactions
to be responsive and efficient. Whereas time cognizant scheduling, concurrency control and conflict resolution have been studied in the literature, recovery issues have not. We have developed strategies for data placement at the appropriate level of memory hierarchy, for avoiding undoing/redoing by exploiting data/transaction characteristics, and for placing logs at the appropriate level in the memory hierarchy. Another issue that we have studied deals with the assignment of priority to transactions in active real-time database systems. We are also studying concurrency control for temporal and multi-media data. We have built RADEx, a simulation environment to evaluate our solutions.
Improving timeliness in real-time secure database systems
Authors: Son Sang H. , David Rasikan , Thuraisingham Bhavani
Published: November 2005

Database systems for real-time applications must satisfy timing constraints associated with transactions, while maintaining data consistency. In addition to real-time requirements, security is usually required in many applications. Multilevel security requirements introduce a new dimension to transaction processing in real-time database systems. In this paper, we argue that because of the complexities involved, trade-offs need to be made between security and timeliness. We briefly present the secure two-phase locking protocol and discuss an adaptive method to support trading off security for timeliness, depending on the current state of the system. The performance of the adaptive secure two-phase locking protocol shows improved timeliness. We also discuss future research direction to improve timeliness of secure database systems.
A note on the translation of SQL to tuple calculus
Authors: Gogolla Martin
Published: November 2005

This note presents a translation of a subset of the relational query language SQL into the well known tuple calculus. Roughly speaking, tuple calculus corresponds to first order predicate calculus. The SQL subset is relationally complete and represents a “relational core” of the language. Nevertheless, our translation is simple and elegant. Therefore it is especially well suited as a beginners course into the principles of a formal definition of SQL.
Query optimization by simulated annealing
Authors: Ioannidis Yannis E. , Wong Eugene
Published: November 2005

Query optimizers of future database management systems are likely to face large access plan spaces in their task. Exhaustively searching such access plan spaces is unacceptable. We propose a query optimization algorithm based on
simulated annealing
, which is a probabilistic hill climbing algorithm. We show the specific formulation of the algorithm for the case of optimizing complex non-recursive queries that arise in the study of linear recursion. The query answer is explicitly represented and manipulated within the
closed semiring
of linear relational operators. The optimization algorithm is applied to a state space that is constructed from the equivalent algebraic forms of the query answer. A prototype of the simulated annealing algorithm has been built and few experiments have been performed for a limited class of relational operators. Our initial experience is that, in general, the algorithm converges to processing strategies that are very close to the optimal. Moreover, the traditional processing strategies (e.g., the
semi-naive evaluation
) have been found to be, in general, suboptimal.
On the representation and querying of sets of possible worlds
Authors: Abiteboul Serge , Kanellakis Paris , Grahne Gosta
Published: November 2005

We represent a
set of possible worlds
using an incomplete information database. The representation techniques that we study form a hierarchy, which generalizes relations of constants. This hierarchy ranges from the very simple Codd-table, (i e , a relation of constants and distinct variables called nulls, which stand for values present but unknown), to much more complex mechanisms involving views on conditioned-tables, (i e , queries on Codd-tables together with conditions). The views we consider are the queries that have polynomial data-complexity on complete information databases. Our conditions are conjunctions of equalities and inequalities.

(1) We provide matching upper and lower bounds on the data-complexity of testing
containement
,
membership
, and
uniqueness
for sets of possible worlds and we fully classify these problems with respect to our representation hierarchy. The most surprising result in this classification is that it is complete in
Π
2
p
, whether a set of possible worlds represented by a Codd-table is a subset of a set of possible worlds represented by a Codd-table with one conjuction of inequalities.

(2) We investigate the data-complexity of querying incomplete information databases. We examine both asking for
certain facts
and for
possible facts
. Our approach is algebraic but our bounds also apply to logical databases. We show that asking for a certain fact is coNP-complete, even for a fixed first order query on a Codd-table. We thus strengthen a lower bound of [16], who showed that this holds for a Codd-table with a conjunction of inequalities. For each fixed positive existential query we present a polynomial algorithm solving the bounded possible fact problem of this query on conditioned-tables. We show that our approach is, in a sense, the best possible, by deriving two NP-completeness lower bounds for the bounded possible fact problem when the fixed query contains either negation or recursion.
Handling redundancy in the processing of recursive database queries
Authors: Han Jiawei , Henschen Lawrence J.
Published: November 2005

Redundancy may exist in the processing of recursive database queries at four different levels precompilation level, iteration level, tuple processing level and file accessing level. Techniques for reducing redundant work at each level are studied. In the precompilation level, the optimization techniques include removing redundant parts in a rule cluster, simplifying recursive clusters and sharing common subexpressions among rules. At the iteration level, the techniques discussed are the use of frontier relations and the counting method. At the tuple processing level, we use merging and filtering methods to exclude processed drivers from database reaccessing. Finally, at the file accessing level, I/O cost can be further reduced by level relaxation. We conclude that even for complex recursion, redundant database processing can be considerably reduced or eliminated by developing appropriate algorithms.
The EXODUS optimizer generator
Authors: Graefe Goetz , DeWitt David J.
Published: November 2005

This paper presents the design and an initial performance evaluation of the query optimizer generator designed for the EXODUS extensible database system. Algebraic transformation rules are translated into an executable query optimizer, which transforms query trees and selects methods for executing operations according to cost functions associated with the methods. The search strategy avoids exhaustive search and it modifies itself to take advantage of past experience. Computational results show that an optimizer generated for a relational system produces access plans almost as good as those produced by exhaustive search, with the search time cut to a small fraction.
The BANG file: A new kind of grid file
Authors: Freeston Michael
Published: November 2005

A new multi-dimensional file structure has been developed in the course of a project to devise ways of improving the support for interactive queries to database and knowledge bases. Christened the 'BANG' file - a Balanced And Nested Grid - the new structure is of the 'grid file' type, but is fundamentally different from previous grid file designs in that it does not share their common underlying properties. It has a tree-structured directory which has the self-balancing property of a B-tree and which, in contrast to previous designs, always expands at the same rate as the data, whatever the form of the data distribution. Its partitioning strategy both accurately reflects the clustering of points in the data space, and is flexible enough to adapt gracefully to changes in the distribution.
Why ROSE is fast: Five optimizations in the design of an experimental database system for CAD/CAM applications
Authors: Hardwick Martin
Published: November 2005

ROSE is an experimental database system for CAD/CAM applications that organizes a database into entries and relationships. The data model of ROSE is an extension of the relational model and the data manipulation language is an extension of the relational algebra. Internally, ROSE is organized so that it can use operating system services to implement database system services. In this paper we describe five optimizations that have helped to make ROSE a fast database system for CAD/CAM.
A necessary condition for a doubly recursive rule to be equivalent to a linear recursive rule
Authors: Zhang Weining , Yu C. T.
Published: November 2005

Nonlinear recursive queries are usually less efficient in processing than linear recursive queries. It is therefore of interest to transform non-linear recursive queries into linear ones. We obtain a necessary and sufficient condition for a doubly recursive rule of a certain type to be logically equivalent to a single linear recursive rule obtained in a specific way.
On the modes and meaning of feedback to transaction designers
Authors: Stemple David , Mazumdar Subhasish , Sheard Tim
Published: November 2005

An analysis of database transactions in the presence of database integrity constraints can lead to several modes of feedback to transaction designers. The different kinds of feedback include tests and updates that could be added to the transaction to make it obey the integrity constraints, as well as predicates representing post-conditions guaranteed by a transaction's execution. We discuss the various modes, meanings, and uses of feedback. We also discuss methods of generating feedback from integrity constraints, transaction details and theorems constituting both generic knowledge of database systems and specific knowledge about a particular database. Our methods are based on a running system that generates tailored theories about database systems from their schemas and uses these theories to prove that transactions obey integrity constraints.
Benchmarking simple database operations
Authors: Rubenstein W. B. , Kubicar M. S. , Cattell R. G. G.
Published: November 2005

There are two widely-known benchmarks for database management systems the TP1 benchmarks (Anon
et al
[1985]), designed to measure transaction throughout, and the Wisconsin benchmarks (Bitton, Dewitt, & Turbyfil [1984]), designed to measure the performance of a relational query processor. In our work with databases on engineering workstations, we found neither of these benchmarks a suitable measure for our applications' needs. Instead, our requirements are for
response time
for simple queries. We propose benchmark measurements to measure response time, specifically designed for the simple, object-oriented queries that engineering database applications perform. We report results from running this benchmark against some database systems we use ourselves, and provide enough detail for others to reproduce the benchmark measurements on other relational, object-oriented, or specialized database systems. We discuss a number of factors that make an order of magnitude improvement in benchmark performance caching the entire database in main memory, avoiding query optimization overhead, using physical links for prejoins, and using an alternative to the generally-accepted database “server” architecture on distributed networks.
Logical modeling of temporal data
Authors: Segev Arie , Shoshani Arie
Published: November 2005

In this paper we examine the semantics and develop constructs for temporal data independent of any traditional data model, such as the relational or network data models. Unlike many other works which extend existing models to support temporal data, our purpose is to characterize the properties of temporal data and operators over them without being influenced by traditional models which were not specifically designed to model temporal data. We develop data constructs that represent sequences of temporal values, identify their semantic properties, and define operations over these structures.
Object-oriented database support for software environments
Authors: Hudson Scott E. , King Roger
Published: November 2005

Cactis is an object-oriented, multi-user DBMS developed at the University of Colorado. The implementation is self-adaptive and concurrent, and runs in the Unix/C Sun workstation environment. A central, unique focus of Cactis is the support of functionally-defined data in a manner which provides good performance. Cactis is intended for use in applications which are conducive to an object-oriented approach and involve derived data. Such applications include software environments.

Cactis supports the construction of objects and type/subtype hierarchies, which are useful for managing the complex and highly-interrelated data found in software environments. Such data types include programs, requirement specifications, milestone reports, configurations, documentation, and many others. Cactis uses techniques based on attributed graphs to ensure that functionally-defined attributes of objects, such as compilation dependencies, cost calculations, and milestone dependencies can be maintained efficiently. Since it is necessary to dynamically add new tools (such as debuggers and compilers) to a software environment, the DBMS allows the user to extend the type structure. The system also supports an efficient rollback and recovery mechanism, which provides the framework for a software version facility.
Enhancing availability in distributed real-time databases
Authors: Lin Kwei-Jay , Lin Ming-Ju
Published: November 2005

One of the issues in distributed databases is to maintain the data consistency when a database is replicated for higher availability. In a real-time database system, availability may be more important than consistency since a result must be produced before a deadline. We propose techniques to increase the availability in a partitioned real-time database. We also suggest that a transaction may execute even when the most up-to-date information is not available or when a serializable execution cannot be guaranteed. As long as data integrity is maintained, serializable execution may not be necessary.
Scheduling real-time transactions
Authors: Abbott Robert , Garcia-Molina Hector
Published: November 2005

Scheduling transactions with real-time requirements presents many new problems. In this paper we discuss solutions for two of these problems: what is a reasonable method for modeling real-time constraints for database transactions? Traditional hard real-time constraints (e.g., deadlines) may be too limited. May transactions have soft deadlines and a more flexible model is needed to capture these soft time constraints. The second problem we address is scheduling. Time constraints add a new dimension to concurrency control. Not only must a schedule be serializable but it also should meet the time constraints of all the transactions in the schedule.
The design and performance evaluation of alternative XML storage strategies
Authors: Tian Feng , DeWitt David J. , Chen Jianjun , Zhang Chun
Published: November 2005

This paper studies five strategies for storing XML documents including one that leaves documents in the file system, three that use a relational database system, and one that uses an object manager. We implement and evaluate each approach using a number of XQuery queries. A number of interesting insights are gained from these experiments and a summary of the advantages and disadvantages of the approaches is presented.
Supporting global user profiles through trusted authorities
Authors: Cingil Ibrahim
Published: November 2005

Personalization generally refers to making a Web site more responsive to the unique and individual needs of each user. We argue that for personalization to work effectively, detailed and interoperable user profiles should be globally available for authorized sites, and these profiles should dynamically reflect the changes in user interests.Creating user profiles from user click-stream data seems to be an effective way of generating detailed and dynamic user profiles. However a user profile generated in this way is available only on the computer where the user accesses his browser, and is inaccessable when the same user works on a different computer. On the other hand, the integration of Internet with telecommunication networks have made it possible for the users to connect to Web with a variety of mobile devices as well as desk tops. This requires that user profiles should be available to any desktop or mobile device on the Internet that users choose to work with.In this paper, we address these problems through the concept of "Trusted Authority". A user agent at the client side that captures the user click stream, dynamically generates a navigational history 'log' file in Extensible Markup Language (XML). This log files is then used to produce the 'user profiles' in Resource Description Framework (RDF). User's right to privacy is provided through the Platform for Privacy Preferences (P3P) standard. User profiles are uploaded to the trusted authority and served next time the user connects to the Web.The trusted authority concept, serving as a namespace qualifier, provides globally unique userid/password identification for users. Furthermore user profiles dynamically reflect the changes in their interests since the data generated while they are surfing the Web contribute to their profile. Also since the user profiles are defined in RDF, they are interoperable and available to any type of authorized device on the Internet.
The n-tier hub technology
Authors: Sommer Rainer A. , Gulledge Thomas R. , Bailey David
Published: November 2005

During 2001, the Enterprise Engineering Laboratory at George Mason University was contracted by the Boeing Company to develop an eHub capability for aerospace suppliers in Taiwan. In a laboratory environment, the core technology was designed, developed, and tested, and now a large first-tier aerospace supplier in Taiwan is commercializing the technology. The project objective was to provide layered network and application services for transporting XML-based business transaction flows across multi-tier, heterogeneous data processing environments. This paper documents the business scenario, the eHub application, and the network transport mechanisms that were used to build the n-tier hub. Contrary to most eHubs, this solution takes the point of view of suppliers, pushing data in accordance with supplier requirements; hence, enhancing the probability of supplier adoption. The unique contribution of this project is the development of an eHub that meets the needs of Small and Medium Enterprises (SMEs) and first-tier suppliers.
A multi-agent system infrastructure for software component market-place
Authors: Erdur Riza Cenk , Dikenelli Oğuz
Published: November 2005

In this paper, we introduce a multi-agent system architecture and an implemented prototype for software component market-place. We emphasize the ontological perspective by discussing the ontology modeling for component market-place, UML extensions for ontology modeling, and the idea of ontology transfer which makes the multi-agent system to adapt itself to the dynamically changing ontologies.
The XML typechecking problem
Authors: Suciu Dan
Published: November 2005

When an XML document conforms to a given type (e.g. a DTD or an XML Schema type) it is called a
valid
document. Checking if a given XML document is valid is called the validation problem, and is typically performed by a parser (hence,
validating parser
), more precisely it is performed right after parsing, by the same program module. In practice however XML documents are often generated dynamically, by some program: checking whether all XML documents generated by the program are valid w.r.t. a given type is called the typechecking problem. While a validation analyzes an XML document, a type checker analyzes a program, and the problem's difficulty is a function of the language in which that program is expressed. The XML typechecking problem has been investigated recently in [MSV00, HP00, HVP00, AMN
+
01a, AMN
+
01b] and the XQuery Working Group adopted some of these techniques for typechecking XQuery [FFM
+
01]). All these techniques, however, have limitations which need to be understood and further explored and investigated. In this paper we define the XML typechecking problem, and present current approaches to typechecking, discussing their limitations.
Why I like working in academia
Authors: Snodgrass Richard Thomas
Published: November 2005

When Alex Labrinidis asked me to write this essay, I initially balked. I was loathe to speak for academics worldwide, or even just those in SIGMOD. But I then realized that I could speak from personal experience. So these random musings will be of necessity entirely subjective, highly individualistic, and unrepresentative---attributes that a scholar normally attempts to vigorously avoid in his writing. I'm definitely not a "typical" academic (I don't know such an animal), but I can speak with some authority as to what motivates
me.
As another caveat, I make few comparisons with alternatives such as working in a research lab or as a developer. I won't even attempt to speak for them.The final caveat (distrust all commentaries that start with caveats, but perhaps more so those that don't!) is that my assumed audience comprises students who are considering such a profession. Current academics will find some of my observations trite or may disagree loudly, as academics are oft to do (see below).That said, I have been an academic for exactly twenty years, and I deeply love the academic life. While I have consulted for and written papers with those away from the ivory tower, my professional life has been entirely as a professor. I went forthwith from undergraduate school to graduate school, then directly to the University of North Carolina, then to the University of Arizona, where I am happily ensconced.I open with some disadvantages to this seemingly ideal life, then turn to the advantages. With each I start with those that I expected when I was a doctoral student, and then consider those I (naïvely or otherwise) was not aware of from that early vantage point.
Deadlock detection is really cheap
Authors: Jiang Bin
Published: November 2005

The treatment of deadlock has previously been considered as expensive, and implementations of the involved algorithm have appeared rather complex. In this paper a new algorithm for the treatment of deadlock is described. It is not only very efficient (in the worst case O(
e
) where
e
is the number of the edges in the “wait-for” graph) but also fairly simple. With this algorithm one can detect all deadlocks as soon as possible and list all participators in the corresponding cycle of the “wait-for” graph. The algorithm is described for the use of database transaction management.
Reference model for DBMS user facility
Authors: Gersting John , Kinsley Kate , McDonald Nancy , North John , Sastry Mark , Stull Edward
Published: November 2005

This report is a contribution to X3/SPARC Database system Study Group (DBSSG). The technical work represents the careful distillation of the contribution of the authors and others who have participated in the meetings and studies of the User Facility Task Group (UFTG) which is a sub-group of the DBSSG.
Implementation of a Prolog-INGRES interface
Authors: Ghosh S. , Lin C. C. , Sellis T.
Published: November 2005

This report describes a working prototype of a Prolog-INGRES interface based on external semantic query simplification. Semantic query simplification employs integrity constraints enforced in a database system for reducing the number of tuple variables and terms in a relational query. This type of query simplifier is useful in providing very high level user interfaces to existing database systems. The system employes a graph theoretic approach to simplify arbitrary conjunctive queries with inequalities. One very interesting feature of the system is to provide meaningful error messages in case of an empty query result resulting from contradiction. In addition to data, rules are stored in the database as well and are retrieved automatically if the Prolog program references them but they are not defined in the Prolog rulebase.
Astronomy from large databases: scientific objectives and methodological approaches
Authors: Murtagh F.
Published: November 2005

The role of databases is increasing continually in astronomy. So too is the need for applicable analysis methods to use on large collections of data. The need, for example, for suitable statistical tools and for experimentation in knowledge based approaches are both related to the growing quantities of astronomical data. The latter areas, and of course astrophysics, — the “scientific objectives and methodological approaches” part of the title — were the initial aim of this conference. But it is clear also that there is an urgent need to coordinate technical database issues. In all of these aspects, the papers in the proceedings volume resulting from this conference will be found to provide valuable introductory and reference material.
Bringing order to query optimization
Authors: Slivinskas Giedrius , Jensen Christian S. , Snodgrass Richard Thomas
Published: November 2005

A variety of developments combine to highlight the need for respecting order when manipulating relations. For example, new functionality is being added to SQL to support OLAP-style querying in which order is frequently an important aspect. The set- or multiset-based frameworks for query optimization that are currently being taught to database students are increasingly inadequate.This paper presents a foundation for query optimization that extends existing frameworks to also capture ordering. A list-based relational algebra is provided along with three progressively stronger types of algebraic equivalences, concrete query transformation rules that obey the different equivalences, and a procedure for determining which types of transformation rules are applicable for optimizing a query. The exposition follows the style chosen by many textbooks, making it relatively easy to teach this material in continuation of the material covered in the textbooks, and to integrate this material into the textbooks.
The design of a retrieval technique for high-dimensional data on tertiary storage
Authors: Orlandic Ratko , Lukaszuk Jack , Swietlik Craig
Published: November 2005

In high-energy physics experiments, large particle accelerators produce enormous quantities of data, measured in hundreds of terabytes or petabytes per year, which are deposited onto tertiary storage. The experiments are designed to study the collisions of fundamental particles, called "events", each of which is represented as a point in a multi-dimensional universe. In these environments, the best retrieval performance can be achieved only if the data is clustered on the tertiary storage by all searchable attributes of the events. Since the number of these attributes is high, the underlying data-management facility must be able to cope with extremely large volumes and very high dimensionalities of data at the same time. The proposed indexing technique is designed to facilitate both clustering and efficient retrieval of high-dimensional data on tertiary storage. The structure uses an original space-partitioning scheme, which has numerous advantages over other space-partitioning techniques. While the main objective of the design is to support high-energy physics experiments, the proposed solution is appropriate for many other scientific applications.
A pictorial query language for querying geographic databases using positional and OLAP operators
Authors: Pourabbas Elaheh , Rafanelli Maurizio
Published: November 2005

The authors propose a declarative Pictorial Query Language (called PQL) that is able to express queries on an Object-Oriented geographic database drawing the features which form the query. These features refer to the classic ones of a geographic environment (geo-null, geo-points, geo-polyline, and geo-region) and define the alphabet of the above mentioned language. This language, extended with respect to a previous one, considers twelve positional operators and a set of their specifications. Moreover, the possibility to use the mentioned language to query multidimensional databases is discussed. Finally, the characteristic of the mentioned language by a query example is shown.
Report on the ACM fourth international workshop on data warehousing and OLAP (DOLAP 2001)
Authors: Hammer Joachim
Published: November 2005

The Fourth Annual ACM International Workshop on Data Warehousing and Online Analytical Processing (DOLAP 2001) was held in Atlanta, GA, USA, in November 2001, in conjunction with the Tenth International Conference on Information and Knowledge Management (CIKM 2001). Although this was only the fourth annual meeting, DOLAP has already become an important and broadly accepted forum for researchers and practitioners to share their findings in theoretical foundations, current methodologies, practical experiences, and new research directions in the areas of data warehousing and online analytical processing (OLAP). Despite the fact that conference attendance has been down since the horrific events of September 11, DOLAP 2001 attracted researchers from Europe, Asia and the Americas.The DOLAP 2001 program, which occupied a full day immediately following CIKM 2001, included a keynote talk, technical presentations, and a final discussion involving all workshop participants. As in previous years, the quality of the submitted papers was high and the program committee had a difficult time deciding which of the 31 submissions from 16 different countries should be accepted for presentation. The submitted research papers covered the state-of-the-art in data warehousing and related fields including data warehouse architecture, design and evolution, multi-dimensional modeling, query optimization, indexing, view materialization and maintenance, data warehouse quality, XML- and object-based warehouses, and data warehousing and the Web. In addition, the committee received a number of industrial submissions describing ongoing data warehousing projects and novel applications for warehouses. After careful review, 12 research and industrial papers were selected for presentation at DOLAP 2001. The proceedings are published by ACM Press, and are also available online at www.informatik.uni-trier.de/~ley/db/conf/dolap/dolap2001.html.In addition, the authors of the three highest-ranked papers have been invited to submit an updated, more detailed version to the Special Issue on Advances in Data Warehousing of the Data and Knowledge Engineering Journal to be published in early 2003.
Phoenix project
Authors: Barga Roger , Lomet David
Published: November 2005

After a system crash, databases recover to the last committed transaction, but applications usually either crash or cannot continue. The Phoenix purpose is to enable application state to persist across system crashes, transparent to the application program. This simplifies application programming, reduces operational costs, masks failures from users, and increases application availability, which is critical in many scenarios, e.g., e-commerce. Within the Phoenix project, we have explored how to provide application recovery efficiently and transparently via redo logging. This paper describes the conceptual framework for the Phoenix project, and the software infrastructure that we are building.
A critique of ANSI SQL isolation levels
Authors: Berenson Hal , Bernstein Phil , Gray Jim , Melton Jim , O'Neil Elizabeth , O'Neil Patrick
Published: November 2005

ANSI SQL-92 [MS, ANSI] defines Isolation
Levels
in terms of
phenomena:
Dirty Reads, Non-Repeatable Reads, and Phantoms. This paper shows that these phenomena and the ANSI SQL definitions fail to properly characterize several popular isolation levels, including the standard locking implementations of the levels covered. Ambiguity in the statement of the phenomena is investigated and a more formal statement is arrived at; in addition new phenomena that better characterize isolation types are introduced. Finally, an important multiversion isolation type, called Snapshot Isolation, is defined.
Parallel evaluation of multi-join queries
Authors: Wilschut Annita N. , Flokstra Jan , Apers Peter M. G.
Published: November 2005

A number of execution strategies for parallel evaluation of multi-join queries have been proposed in the literature; their performance was evaluated by simulation. In this paper we give a comparative performance evaluation of four execution strategies by implementing all of them on the same parallel database system, PRISMA/DB. Experiments have been done up to 80 processors. The basic strategy is to first determine an execution schedule with minimum total cost and then parallelize this schedule with one of the four execution strategies. These strategies, coming from the literature, are named:
Sequential Parallel, Synchronous Execution, Segmented Right-Deep,
and
Full Parallel.
Based on the experiments clear guidelines are given when to use which strategy.
The merge/purge problem for large databases
Authors: Hernández Mauricio A. , Stolfo Salvatore J.
Published: November 2005

Many commercial organizations routinely gather large numbers of databases for various marketing and business analysis functions. The task is to correlate information from different databases by identifying distinct individuals that appear in a number of different databases typically in an inconsistent and often incorrect fashion. The problem we study here is the task of merging data from multiple sources in as efficient manner as possible, while maximizing the accuracy of the result. We call this the
merge/purge
problem. In this paper we detail the
sorted neighborhood
method that is used by some to solve merge/purge and present experimental results that demonstrates this approach may work well in practice but at great expense. An alternative method based upon clustering is also presented with a comparative evaluation to the sorted neighborhood method. We show a means of improving the accuracy of the results based upon a
multi-pass
approach that succeeds by computing the Transitive Closure over the results of independent runs considering alternative primary key attributes in each pass.