bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and evaluation of parallel pipelined join algorithms
Authors: Richardson James P. , Lu Hongjun , Mikkilineni Krishna 
Published: November 2005

The join operation is the most costly operation in relational database management systems. Distributed and parallel processing can effectively speed up the join operation. In this paper, we describe a number of highly parallel and pipelined multiprocessor join algorithms using sort-merge and hashing techniques. Among them, two algorithms are parallel and pipelined versions of traditional sort-merge join methods, two algorithms use both hashing and sort-merge techniques, and another two are variations of the hybrid hash join algorithms. The performance of those algorithms is evaluated analytically against a generic database machine architecture. The methodology used in the design and evaluation of these algorithms is also discussed.
The results of the analysis indicate that using a hashing technique to partition the source relations can dramatically reduce the elapsed time hash-based algorithms outperform sort-merge algorithms in almost all cases because of their high parallelism. Hash-based sort-merge and hybrid hash methods provide similar performance in most cases. With large source relations, the algorithms which replicate the smaller relation usually give better elapsed time. Sharing memory among processors also improves performance somewhat.
Issues and approaches to design of real-time database systems
Authors: Singhal Mukesh 
Published: November 2005

Real-time database systems support applications which have severe performance constraints such as fast response time and continued operation in the face of catastrophic failures. Real-time database systems are still in the state of infancy, and issues and alternatives in their design are not very well explored. In this paper, we discuss issues in the design of real-time database systems and discuss different alternatives for resolving these issues. We discuss the aspects in which requirements and design issues of real-time database systems differ from those of conventional database systems. We discuss two approaches to design real-time database systems, viz., main memory resident databases and design by trading a feature (like serializability).
We also discuss requirements in the design of real-time distributed database systems, and specifically discuss issues in the design of concurrency control and crash recovery. It is felt that long communication delays may be a factor in limiting the performance of real-time distributed database systems. We present a concurrency control algorithm for real-time distributed database systems whose performance is not limited by communication delays.
Integration approaches for CIM
Authors: Norrie Moira C. 
Published: November 2005

In response to pressures to reduce product lead times, manufacturing companies are increasingly aware of the need for some form of integration along the whole product chain. Engineering tasks must be coordinated and data exchanged between the various specialised tools. An enterprise has two main tracks of information flow, namely technical and managerial, and product data management spans both tracks. On the technical track, applications are highly specialised supporting tasks such as product design (CAD) and the programming of numerically controlled machines (CAM). Generally, the various application systems on the technical track are referred to as CAx systems. CAx systems may not only differ in terms of functionality but also in terms of the amount and type of data managed, the run-time environment and performance characteristics.
For complete support of Computer Integrated Manufacturing (CIM), we must be able to integrate existing technical and administrative component application systems. These component systems vary in their data management support and many CAx systems store their data directly in files rather than in a database system. The issues are how to describe the dependencies between these component systems and ensure system-wide data consistency. A particularly difficult problem is that of how to interface existing application systems in such a way that their operation can be monitored and controlled and a global transaction scheme provided.
Integration must be achieved in a way that supports system evolution in terms of the introduction and replacement of application systems. This is particularly important given the trend towards the notions of the extended enterprise and virtual factories in which a particular product chain may span several enterprises. Further, emerging legal statutes (especially in relation to environmental factors) are resulting in changes to the requirements for product data management. Enterprise integration must be both flexible and dynamic. The best way of achieving this is to integrate component systems by mans of a control layer which coordinates tasks based on explicit inter-system dependencies amenable to both direct view and update.
Product Data Management systems (also known as Engineering Databases) have been developed for the integration of CAx systems by managing product data centrally. One problem with a centralised system controlling access to data is that its availability is critical to the operation of all component systems. In an effort to overcome this, systems are being developed which replicate the metadata and data required for coordination.
Alternatively, coordination approaches have been proposed which aim to maximise component subsystem autonomy and increase CIM system flexibility. These systems place less emphasis on data sharing and more emphasis on task coordination. The integration effort is minimised and only that information strictly essential to coordination is managed centrally.
CLASSIC: a structural data model for objects
Authors: Borgida Alexander , Brachman Ronald J. , McGuinness Deborah L. , Resnick Lori Alperin 
Published: November 2005

CLASSIC is a data model that encourages the description of objects not only in terms of their relations to other known objects, but in terms of a level of intensional structure as well. The CLASSIC language of
structured descriptions
permits i) partial descriptions of individuals, under an 'open world' assumption, ii) answers to queries either as extensional lists of values or as descriptions that necessarily hold of all possible answers, and iii) an easily extensible schema, which can be accessed uniformly with the data. One of the strengths of the approach is that the same language plays multiple roles in the processes of defining and populating the DB, as well as querying and answering.

CLASSIC (for which we have a prototype main-memory implementation) can actively discover new information about objects from several sources: it can recognize new classes under which an object falls based on a description of the object, it can propagate some deductive consequences of DB updates, it has simple procedural recognizers, and it supports a limited form of forward-chaining rules to derive new conclusions about known objects.
The kind of language of descriptions and queries presented here provides a new arena for the search for languages that are more expressive than conventional DBMS languages, but for which query processing is still tractable. This space of languages differs from the subsets of predicate calculus hitherto explored by deductive databases.
Processing aggregate relational queries with hard time constraints
Authors: Hou Wen-Chi , Ozsoyoglu Gultekin , Taneja Baldeo K. 
Published: November 2005

We consider those database environments in which queries have strict timing constraints, and develop a time-constrained query evaluation methodology. For aggregate relational algebra queries, we describe a time constrained query evaluation algorithm. The algorithm, which is implemented in our prototype DBMS, iteratively samples from input relations, and evaluates the associated estimators developed in our previous work, until a stopping criterion (e.g., a time quota or a desired error range) is satisfied.
To determine sample sizes at each stage of the iteration (so that the time quota will not be overspent) we need to have (a) accurate sample selectivity estimations of the RA operators in the query, (b) precise time cost formulas, and (c) good time-control strategies. To estimate the sample selectivities of RA operators, we use a runtime sample selectivity estimation and improvement approach which is flexible. For query time estimations, we use time-cost formulas which are adaptive and precise. To use the time quota efficiently, we propose statistical and heuristic time-control strategies to control the risk of overspending the time quota. Preliminary evaluation of the implemented prototype is also presented.
Extending a relational database with deferred referential integrity checking and intelligent joins
Authors: Cammarata Stephanie , Ramachandra Prasadram , Shane Darrell 
Published: November 2005

Interactive use of relational database management systems (DBMS) requires a user to be knowledgeable about the semantics of the application represented in the database. In many cases, however, users are not trained in the application field and are not DBMS experts. Two categories of functionality are problematic for such users: (1) updating a database without violating integrity constraints imposed by the domain and (2) using join operations to retrieve data from more than one relation. We have been conducting research to help an uninformed or casual user interact with a relational DBMS.
This paper describes two capabilities to aid an interactive database user who is neither an application specialist nor a DBMS expert. We have developed deferred Referential Integrity Checking (RIC) and Intelligent Join (IJ) which extend the operations of a relational DBMS. These facilities are made possible by explicit representation of database semantics combined with a relational schema. Deferred RIC is a static validation procedure that checks uniqueness of tuples, non-null keys, uniqueness of keys, and inclusion dependencies. IJ allows a user to identify only the “target” data which is to be retrieved without the need to additionally specify “join clauses”. In this paper we present the motivation for these facilities, describe the features of each, and present examples of their use.
Retrieval performance versus disc space utilization on WORM optical discs
Authors: Christodoulakis Stavros , Ford Daniel Alexander 
Published: November 2005

Steady progress in the development of optical disc technology over the past decade has brought it to the point where it is beginning to compete directly with magnetic disc technology. WORM optical discs in particular, which permanently register information on the disc surface, have significant advantages over magnetic technology for applications that are mainly archival in nature but require the ability to do frequent on-line insertions.
In this paper, we propose a class of access methods that use rewritable storage for the temporary buffering of insertions to data sets stored on WORM optical discs and we examine the relationship between the retrieval performance from WORM optical discs and the utilization of disc storage space when one of these organizations is employed. We describe the performance trade off as one of fast sequential retrieval of the contents of a block versus wasted space owing to data replication. A model of a specific instance of such an organization (a buffered hash file scheme) is described that allows for the specification of retrieval performance objectives. Alternative strategies for managing data replication that allow trade offs between higher consumption rates and better average retrieval performance are also described. We then provide an expected value analysis of the amount of disc space that must be consumed on a WORM disc to meet specified performance limits. The analysis is general enough to allow easy extension to other types of buffered files systems for WORM optical discs.
Rules for implementing very large knowledge base systems
Authors: Bocca J. B. , Freytag J. C. 
Published: November 2005

With the current research effort in knowledge base management systems (KBMSs) the interest in storing, retrieving, and processing rules efficiently, and using them for describing and implementing such systems has increased significantly. In this paper we contribute to this subject in two ways. First, we introduce Educe*, an integrated programming system for building large knowledge base systems. In particular, we describe the treatment of rules and complex logic terms, examine at the physical level the compilation of logic programs and its subsequent storage, retrieval and execution in the specified context, and discuss performance related aspects of our system.
Second, we provide an overview on how to use rules for organizing the processing of user requests in a database/knowledge base environment. Specifically, we discuss aspects of rule-based query optimization and compilation. Finally, we outline additional query processing problems that could benefit from a rule-based specification and a rule-driven implementation.
OdeView: the graphical interface to Ode
Authors: Agrawal R. , Gehani N. H. , Srinivasan J. 
Published: November 2005

OdeView is the graphical front end for Ode, an object-oriented database system and environment. Ode's data model supports data encapsulation, type inheritance, and complex objects. OdeView provides facilities for examining the database schema (i.e., the object type or class hierarchy), examining class definitions, browsing objects, following chains of references starting from an object, synchronized browsing, displaying selected portions of objects (projection), and retrieving objects with specific characteristics (selection).
OdeView does not need to know about the internals of Ode objects. Consequently, the internals of specific classes are not hardwired into OdeView and new classes can be added to the Ode database without requiring any changes to or recompilation of OdeView. Just as OdeView does not know about the object internals, class functions (methods) for displaying objects are written without knowing about the specifics of the windowing software used by OdeView or the graphical user interface provided by it.
In this paper, we present OdeView, and discuss its design and implementation.
Linear clustering of objects with multiple attributes
Authors: Jagadish H. V. 
Published: November 2005

There is often a need to map a multi-dimensional space on to a one-dimensional space. For example, this kind of mapping has been proposed to permit the use of one-dimensional indexing techniques to a multi-dimensional index space such as in a spatial database. This kind of mapping is also of value in assigning physical storage, such as assigning buckets to records that have been indexed on multiple attributes, to minimize the disk access effort.
In this paper, we discuss what the desired properties of such a mapping are, and evaluate, through analysis and simulation, several mappings that have been proposed in the past. We present a mapping based on Hilbert's space-filling curve, which out-performs previously proposed mappings on average over a variety of different operating conditions.
Microprocessors for non-numeric processing
Authors: Zaky S. G. 
Published: November 2005

The problem of processing of non-numeric data has received considerable attention in the last few years. This is primarily motivate by the pressing needs in the are a of data base management. It has long been recognized that the parallel processing capabilities of an associative processor are fundamentally well suited to this environment. However, the complexity and cost of truely associative memories make this approach impractical. In this paper, the demands that non-numeric processing place on memory and processor hardware are discussed. Some emerging trends are presented, and a suggestion is given regarding the development of a “general purpose” microprocessor that is suited to this environment.
Basically, the microprocessor discussed here is capable of performing simple search and update functions on a high speed, serial data stream. Therefore, it is suited to any application where such a situation is encountered, such as in digital communications.
The data management machine, a classification
Authors: Rosenthal Robert S. 
Published: November 2005

There has been much interest in the use of special purpose processors as the data base management component of data processing systems. The generic terms “backend” and “data management machine” have been applied to such devices. Examination of the literature reveals a broad cross section of host to backend functional distribution and interconnection methodology. This discussion represents an attempt to examine and classify several of these backend data base management machine configurations in terms of their operational parameters and application constraints. A formal taxonomy of such systems remains yet to be performed.
At least three distinct classes of data management machine (DMM) are evidenced in the literature; they are the large host backend, distributed network data node and smart peripheral. The intended classes of problem that the various authors envision amenable to solution by the DMM approach exhibit overlap while the performance envelope in which each DMM architecture would provide a technically acceptable, economically sound solution to a given user requirement set varies. Some of the papers used as source for this work contained no explicit mention of either the problem classes or performance constraints that the described configuration was to address; thus liberty has been taken in interpreting the implicit application goals of these authors.
Ulisse
Authors: Cerretti R. , Jasilli D. , Matteucci D. R. 
Published: November 2005

The paper describes a project conducted in collaboration between CNUCE, an Institute of the Italian National Research Council, and a private research center, concerning a multifunctional system (Ulisse) capable of operating both as a stand alone unit for office administration and automation (word processsing, file management and retrieval) and as an intelligent terminal with local facilities for text editing, text formatting and storage.
The first results of the application of Ulisse in the environment of the scientific users of CNUCE are illustrated.
Extraordinary Flood Response of a Small Urban Watershed to Short-Duration Convective Rainfall
Authors: Smith James A. , Miller Andrew J. , Baeck Mary Lynn , Nelson Peter A. , Fisher Gary T. , Meierdiercks Katherine L. 
Published: November 2005

Abstract
The 9.1 km2 Moores Run watershed in Baltimore, Maryland, experiences floods with unit discharge peaks exceeding 1 m3 s−1 km−2 12 times yr−1, on average. Few, if any, drainage basins in the continental United States have a higher frequency. A thunderstorm system on 13 June 2003 produced the record flood peak (13.2 m3 s−1 km−2) during the 6-yr stream gauging record of Moores Run. In this paper, the hydrometeorology, hydrology, and hydraulics of extreme floods in Moores Run are examined through analyses of the 13 June 2003 storm and flood, as well as other major storm and flood events during the 2000–03 time period. The 13 June 2003 flood, like most floods in Moores Run, was produced by an organized system of thunderstorms. Analyses of the 13 June 2003 storm, which are based on volume scan reflectivity observations from the Sterling, Virginia, WSR-88D radar, are used to characterize the spatial and temporal variability of flash flood producing rainfall. Hydrology of flood response in Moores Run is characterized by highly efficient concentration of runoff through the storm drain network and relatively low runoff ratios. A detailed survey of high-water marks for the 13 June 2003 flood is used, in combination with analyses based on a 2D, depth-averaged open channel flow model (TELEMAC 2D) to examine hydraulics of the 13 June 2003 flood. Hydraulic analyses are used to examine peak discharge estimates for the 13 June flood peak, propagation of flood waves in the Moores Run channel, and 2D flow features associated with channel and floodplain geometry.
Use of Satellite-Based Precipitation Observation in Improving the Parameterization of Canopy Hydrological Processes in Land Surface Models
Authors: Wang Dagang , Wang Guiling , Anagnostou Emmanouil N. 
Published: November 2005

Abstract
Precipitation exhibits significant spatial variability at scales much smaller than the typical size of climate model grid cells. Neglecting such subgrid-scale variability in climate models causes unrealistic representation of land–atmosphere flux exchanges. It is especially problematic over densely vegetated land. This paper addresses this issue by incorporating satellite-based precipitation observations into the representation of canopy interception processes in land surface models. Rainfall data derived from passive microwave (PM) observations are used to obtain realistic estimates of 1) conditional mean rain rates, which together with the modeled rain rate are used to estimate the rainfall coverage fraction at each model grid cell in this study, and 2) the probability density function (pdf) of rain rates within the rain-covered areas. Both of these properties significantly impact the land–atmosphere water vapor exchanges. Based on the above information, a statistical–dynamical approach is taken to incorporate the representation of precipitation subgrid variability into canopy interception processes in land surface models. The results reveal that incorporation of precipitation subgrid variability significantly alters the partitioning between runoff and total evapotranspiration as well as the partitioning among the three components of evapotranspiration (i.e., canopy interception loss, ground evaporation, and plant transpiration). This further influences soil water, surface temperature, and surface heat fluxes. It is shown that the choice of the rain-rate pdf within rain-covered areas has an effect on the model simulation of land–atmosphere flux exchanges. This study demonstrates that land surface and climate models can substantially benefit from the fine-resolution remotely sensed rainfall observations.
AGCM Biases in Evaporation Regime: Impacts on Soil Moisture Memory and Land–Atmosphere Feedback
Authors: Mahanama Sarith P. P. , Koster Randal D. 
Published: November 2005

Abstract
Because precipitation and net radiation in an atmospheric general circulation model (AGCM) are typically biased relative to observations, the simulated evaporative regime of a region may be biased, with consequent negative effects on the AGCM’s ability to translate an initialized soil moisture anomaly into an improved seasonal prediction. These potential problems are investigated through extensive offline analyses with the Mosaic land surface model (LSM). The LSM was first forced globally with a 15-yr observation-based dataset. The simulation was then repeated after imposing a representative set of GCM climate biases onto the forcings—the observational forcings were scaled so that their mean seasonal cycles matched those simulated by the NASA Seasonal-to-Interannual Prediction Project (NSIPP-1; NASA Global Modeling and Assimilation Office) AGCM over the same period. The AGCM’s climate biases do indeed lead to significant biases in evaporative regime in certain regions, with the expected impacts on soil moisture memory time scales. Furthermore, the offline simulations suggest that the biased forcing in the AGCM should contribute to overestimated feedback in certain parts of North America—parts already identified in previous studies as having excessive feedback. The present study thus supports the notion that the reduction of climate biases in the AGCM will lead to more appropriate translations of soil moisture initialization into seasonal prediction skill.