bluuebunny/crossref_metadata_2025_split huggingface dataset:
Incremental maintenance of recursive views using relational calculus/SQL
Authors: Dong Guozhu , Su Jianwen 
Published: November 2005

Views are a central component of both traditional database systems and new applications such as data warehouses. Very often the desired views (e.g. the transitive closure) cannot be defined in the standard language of the underlying database system. Fortunately, it is often possible to incrementally maintain these views using the standard language. For example, transitive closure of acyclic graphs, and of undirected graphs, can be maintained in relational calculus after both single edge insertions and deletions. Many such results have been published in the theoretical database community. The purpose of this survey is to make these useful results known to the wider database research and development community.
There are many interesting issues involved in the maintenance of recursive views. A maintenance algorithm may be applicable to just one view, or to a class of views specified by a view definition language such as Datalog. The maintenance algorithm can be specified in a maintenance language of different expressiveness, such as the conjunctive queries, the relational calculus or SQL. Ideally, this maintenance language should be less expensive than the view definition language. The maintenance algorithm may allow updates of different kinds, such as just single tuple insertions, just single tuple deletions, special set-based insertions and/or deletions, or combinations thereof. The view maintenance algorithms may also need to maintain auxiliary relations to help maintain the views of interest. It is of interest to know the minimal arity necessary for these auxiliary relations and whether the auxiliary relations are deterministic. While many results are known about these issues for several settings, many further challenging research problems still remain to be solved.
Diluting ACID
Authors: Kempster Tim , Stirling Colin , Thanisch Peter 
Published: November 2005

Several DBMS vendors have implemented the ANSI standard SQL isolation levels for transaction processing. This has created a gap between database practice and textbook accounts of transaction processing which simply equate isolation with serializability.
We extend the notion of conflict to cover lower isolation levels and we present improved characterisations of classes of schedules achieving these levels.
Optimizing multidimensional index trees for main memory access
Authors: Kim Kihong , Cha Sang K. , Kwon Keunjoo 
Published: November 2005

Recent studies have shown that cache-conscious indexes such as the CSB+-tree outperform conventional main memory indexes such as the T-tree. The key idea of these cache-conscious indexes is to eliminate most of child pointers from a node to increase the fanout of the tree. When the node size is chosen in the order of the cache block size, this pointer elimination effectively reduces the tree height, and thus improves the cache behavior of the index. However, the pointer elimination cannot be directly applied to multidimensional index structures such as the R-tree, where the size of a key, typically, an MBR (minimum bounding rectangle), is much larger than that of a pointer. Simple elimination of four-byte pointers does not help much to pack more entries in a node.
This paper proposes a cache-conscious version of the R-tree called the CR-tree. To pack more entries in a node, the CR-tree compresses MBR keys, which occupy almost 80% of index data in the two-dimensional case. It first represents the coordinates of an MBR key relatively to the lower left corner of its parent MBR to eliminate the leading O's from the relative coordinate representation. Then, it quantizes the relative coordinates with a fixed number of bits to further cut off the trailing less significant bits. Consequently, the CR-tree becomes significantly wider and smaller than the ordinary R-tree. Our experimental and analytical study shows that the two-dimensional CR-tree performs search up to 2.5 times faster than the ordinary R-tree while maintaining similar update performance and consuming about 60% less memory space.
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.
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.
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.
Composite objects revisited
Authors: Kim Won , Bertino Elisa , Garza Jorge F. 
Published: November 2005

In object-oriented systems, an object may recursively reference any number of other objects. The references, however, do not capture any special relationships between objects. An important semantic relationship which may be superimposed on a reference is the IS-PART-OF relationship between a pair of objects. A set of objects related by the IS-PART-OF relationship is collectively called a composite object.
An earlier paper [KIM87b] presented a model of composite objects which has been implemented in the ORION object-oriented database system at MCC. Although the composite-object feature has been found quite useful, the model suffers from a number of serious shortcomings, primarily because it overloads a number of orthogonal semantics on the references. In this paper, first we present a more general model of composite objects which does not suffer from these shortcomings. Further, [KIM87b] made an important contribution by exploring the use of composite objects as a unit for versions, physical clustering, and concurrency control. The extended model of composite objects necessitates non-trivial changes to the results of [KIM87b]. This paper describes the new results on the use of composite objects as a unit of not only versions, physical clustering and concurrency control, but also authorization.
Information management directions: the integration challenge
Authors: Fong E. N. , Goldfine A. H. 
Published: November 2005

On October 31 - November 2, 1988, the National Computer Systems Laboratory of the National Institute of Standards and Technology, formerly the National Bureau of Standards, in cooperation with the Association for Computing Machinery Special Interest Group on Management of Data, the IEEE Computer Society Technical Committee on Database Engineering, and the Federal Data Management Users Group, held the fifth in the series of Information Management Directions (formerly called Data Base Directions) workshops. The purpose of these workshops is to examine in depth key trends and strategies that affect the future of the information management profession. The focus of Workshop 5 was on issues related to integration and productivity.
The complete workshop report, INFORMATION MANAGEMENT DIRECTIONS: THE INTEGRATION CHALLENGE, has been published by the National Institute of Standards and Technology as Special Publication 500-167, and can be ordered from the Superintendent of Documents, U.S. Government Printing Office, Washington, DC 20402.
Associative/parallel processors for searching very large textual data bases
Authors: Bird R. M. , Tu J. C. , Worthy R. M. 
Published: November 2005

This paper describes an approach to solving a major problem in the information processing sciences— that of searching very large (5-50 billion characters) data bases of unstructured free-text for random queries within a reasonable time and at an affordable price.
The need by information specialists and knowledge workers for large, fast low-cost text and document retrieval systems is growing rapidly. Conventional approaches to the problem have usually depended upon expensive, general purpose computers, upon special pre-preprocessing of the textual data (e.g. file inverting, indexing, abstracting, etc.), and upon elaborate, costly software. The resulting retrieval systems often cost hundreds of dollars per query and the full scanning of an uninverted, unstructured billion byte textual data base could take hours of computer services. However, in spite of these restrictions, such full text search systems have proved useful and even indispensible for many applications.
Computer technology of the late 1960's and the 1970's, in both hardware and software (e.g., minicomputers, low-cost, high density disk storage, “chip” electronics, natural language query systems, etc.), have made i t practical to build special purpose, low-cost text retrieval systems. Such a system has been built, tested, and is now in a production stage. The system called the Associative File Processor (AFP), utilizes a conventional minicomputer (DEC's PDP-11/45) for control, off-the-shelf high density disks for storage, a special purpose parallel search module as a text term detector, and query and retrieval software. The AFP is currently being field tested at two sites. Full text, parallel searches on un-preprocessed textual data bases are being performed at the effective matching rates of 4 billion bytes per second (8K byte key memory times 500 Kbyte/second data stream). Estimated costs are 10 to 25 cents per query for a one billion byte data base. The costs per query and the time for searching increase in a linear fashion as data base increases. A basic architecture for the AFP is described and an implemented version is discussed. A more powerful term detector module is also under development. This system is designed around a finite state automaton algorithm.
A comparison of sequential and associate computing of priority queues
Authors: Landson Barry M. , Sargent Robert G. 
Published: November 2005

A comparison of priority queues on four different types of computer memories are made by ring a model to determine the total time to do comparable tasks. The four types of memories compared are random access (RAM), associate (AM), hybrid consisting of an associate memory and a random access memory (AM/RAM), and the hybrid memory with an auxiliary memory having the @@@@pability to perform Lewin's Associate algorithm @@@@], (AM/RAM/AML).
The model used for the comparisons is an extension of the MIX model developed by Knuth [1]. The MIX model was extended to include the four types of memories and the instruction set expanded include @@@@ instructions for the memories added. This @@del allows direct comparisons to be made of the different architectures and different software algorithms in performing the same tasks.
Performance analysis and fundamental performance tradeoffs for CLV optical disks
Authors: Christodoulakis Stavros , Ford Daniel Alexander 
Published: November 2005

CLV type optical disks is a very large and important class of optical disk technology, of which CD-ROM disks form a subclass.
In this paper we present a model of retrieval from CLV optical disks. We then provide exact and approximate results analyzing the retrieval performance from them. Our analysis takes into account disks with and without a mirror in the read mechanism, small objects completely placed within block boundaries, placement that allows block boundary crossing, as well as very large objects (such as documents) placed within files.
In the second part of the paper we describe some fundamental implications of physical data base design for data bases stored on CLV optical disks. We show that very significant performance gains may be realized by appropriate design.
Classification of recursive formulas in deductive databases
Authors: Youn Cheong , Henschen Lawrence J. , Han Jiawei 
Published: November 2005

In this paper, we present results on the classification of linear recursive formulas in deductive databases and apply those results to the compilation and optimization of recursive queries. We also introduce compiled formulas and query evaluation plans for a representative query for each of these classes.
To explain general recursive formulas, we use a graph model that shows the connectivity between variables. The connecticity between variables is the most critical part in processing recursive formulas. We demonstrate that based on such a graph model all the linear recursive formulas can be classified into several classes and each class shares some common characteristics in compilation and query processing. The compiled formulas and the corresponding query evaluation plans can be derived based on the study of the compilation of each class.
Commitment in a partitioned distributed database
Authors: Ramarao K. V. S. 
Published: November 2005

Network partition is among the hardest failure types in a distributed system even if all processors and links are offail-stoptype. We address the transaction commitment problem in a partitioned distributed database. It is assumed that partitions are detectable. The approach taken is conservative - that is, the same transaction cannot be committed by one site and aborted by another.A new and very general formal model of protocols operating in a partitioned system is introduced and protocols more efficient than the existing ones are constructed.
The Water Budget of the Kuparuk River Basin, Alaska*
Authors: Déry Stephen J. , Stieglitz Marc , Rennermalm Åsa K. , Wood Eric F. 
Published: November 2005

AbstractA water budget study that considers precipitation, river runoff, evapotranspiration, and soil moisture for the Kuparuk River basin on the North Slope of Alaska is presented. Numerical simulations of hydrologic processes using the NASA Catchment-based Land Surface Model are conducted for the period 1991–2001 and provide the partitioning of the observed precipitation input (292 mm yr−1) onto the basin into river discharge (169 mm yr−1), evapotranspiration (127 mm yr−1), and an increase in soil moisture (1 mm yr−1). Discharge attains its annual peak during snowmelt and disposes 58% of the annual precipitation. Evapotranspiration contributes another 43% to the water budget and is mainly associated with warm summertime conditions and a snow-free surface. Combined, surface-snow and blowing-snow sublimation contribute only 5% of the total annual evaporative fluxes. Soil moisture recharge is associated with snowmelt during spring and rainfall during late summer and early fall, whereas soil drying accompanies high evapotranspiration rates during summer. An analysis of interannual variability in the water budget shows that warm, dry years favor a relatively more intense response of river discharge and evapotranspiration to the precipitation input, whereas cool, wet years tend to augment soil moisture.
Hydrometeorology of the Amazon in ERA-40
Authors: Betts Alan K. , Ball John H. , Viterbo Pedro , Dai Aiguo , Marengo José 
Published: November 2005

Abstract
The hydrometeorology of the Amazon basin in the ERA-40 reanalysis for 1958–2001 is compared with observations of precipitation, temperature, and streamflow. After 1979, the reanalysis over the Amazon has a small cool bias of the order of −0.35 K, and a small low bias of precipitation of the order of −0.3 mm day−1. In the early years (1958–72), there is a large upward drift in reanalysis precipitation and runoff associated with an upward drift in the atmospheric water vapor in the analysis, and a somewhat smaller downward drift of temperature as precipitation increases. In the presatellite data, there are inhomogeneities in the radiosonde and surface synoptic data, and there were problems with the variational analysis of humidity once satellite radiances were introduced. Approximate bias corrections can be made for precipitation and runoff on an annual basis, but this also removes some of the interannual variability. The reanalysis runoff–precipitation relationship is similar to the observed streamflow–precipitation relation, on an annual water-year basis. Compared to observations, ERA-40 precipitation for the Amazon is low by about 1.3 mm day−1 in the rainy season, and high by a smaller amount in the dry season. The precipitation bias produces a temperature bias in ERA-40 of the opposite sign on the annual time scale. The reanalysis has a small cold temperature bias after 1967, but on an annual time scale it reproduces the interannual variability of the observations. Although the biases in temperature and precipitation in recent decades are small, the difficulties with the analysis of atmospheric water vapor lead to large uncertainty in long-term trends of the water cycle.
Uncertainties in Estimating Moisture Fluxes over the Intra-Americas Sea
Authors: Mestas-Nuñez Alberto M. , Zhang Chidong , Enfield David B. 
Published: November 2005

Abstract
This study estimates discrepancies in moisture flux divergence in the Intra-Americas Sea (IAS; including the Gulf of Mexico and the Caribbean Sea) calculated using sounding observations, the NCEP Eta high-resolution regional analysis, and the NCEP–NCAR coarse-resolution global reanalysis. The main purpose of this exercise is to quantify the uncertainties in the global reanalysis when it is used to calculate annual and interannual variability of moisture flux divergence in the region. An accurate estimate of moisture flux divergence is crucial to evaluate whether the IAS serves as a water vapor source for rainfall over the adjacent land. Using the three datasets, the uncertainties of calculated moisture flux divergence due to the design of the boundary of the area, mathematical algorithms, and spatial and temporal resolutions are quantified. The results show that the large seasonal and interannual variability in moisture flux divergence estimated using the NCEP–NCAR reanalysis is not compromised by these uncertainties. Therefore, NCEP–NCAR reanalysis, with its global coverage and long-term record, can be used to provide the best estimate of short climate variability of moisture flux divergence available to date. Further comparisons are made of the moisture flux divergence based on the NCEP–NCAR reanalysis with previous estimates using single-year sounding observations, as well as with multiyear estimates based on global datasets of surface evaporation and precipitation. It is shown that the previous estimates using single-year sounding observations bear large uncertainties because of interannual variability. Large uncertainties also exist in datasets of surface global evaporation and precipitation.
Comparison between Two Extreme NAO Winters and Consequences on the Thermal Regime of Lake Vendyurskoe, Karelia
Authors: Maher Osama Ali , Uvo Cintia Bertacchi , Bengtsson Lars 
Published: November 2005

Abstract
For 10 consecutive winters, measurements were carried out in Lake Vendyurskoe, Karelia, Russia. The aim of these measurements was to investigate some of the physical processes in this small shallow lake during its ice-covered period. Detailed measurements of ice thickness and condition, snow thickness, water temperature, salt content, and currents were developed into a database. Within this database are the winters 1994/95 and 1995/96, which are characterized by a very sharp change between positive and negative phases of the North Atlantic Oscillation (NAO). This note investigates and compares the effects of these two NAO phases on the regional climate and their relation to the thermal regime of Lake Vendyurskoe.
It became clear that the ice-covered period length did not vary much from one winter to the other; however, a large difference was observed in the maximum average ice cover thickness and in the average water temperature at ice formation (e.g., larger thickness and colder water temperature during the 1995/96 winter).